I have research and reached logical and impressive results, but there is a problem that one of the predictions of my theory is that antimatter cannot be found on Earth and cannot be made, and this makes scientific research and experiments that talk about finding antimatter wrong. Could it really be that? The research is wrong and they lied to us about antimatter, or am I wrong? Is it possible to accept a scientific research that contradicts previous scientific experiments and is in line with other experiments?
It is highly unlikely that anyone will accept theory-based research that concludes that a large range of experimental results are impossible to have been observed, even though multiple groups report observing them.
You would have to offer an alternative explanation for why those groups have observed what they have, or accuse not just one scientist, or even one group, but multiple groups across the world of lying, which is unlikely to ever be accepted.
In almost all cases in science, experimental evidence trumps theory.
It's certainly possible to accept research that falsifies several experiments.* Einstein's theory of relativity has come to be accepted even though it falsified mountains of experimental evidence for Newtonian mechanics.
But there's one very important thing Einstein's theory did: it is able to explain why previous experiments saw the evidence for Newtonian mechanics. It is able to explain why those experiments didn't see deviations (e.g. speed not large enough), and it is able to predict where to look to find deviations. Put differently, Einstein's theory reduces to Newtonian mechanics in the limit of small masses and small speeds. If it didn't, it would never work.
Any new theory needs to be able to explain why the old theory seems to work. If your theory claims that antimatter does not exist, it must also be able to explain why so many experiments, conducted by different people across different generations, appear to see antimatter. It must be able to explain why PET scanners used by doctors works even though positrons don't exist. If it's not able to do this, your new theory is dead before it even begins and no physicist will pay it serious attention.
*Here by "falsifies several experiments" I mean "falsifies a theory that was previously accepted as the explanation for several experiments".
Experiments are the arbiter of what's correct. Given this, an experiment cannot be falsified by theory, as many commenters have said.
I'd like to add another angle to the existing responses. Experiments need to be interpreted in the light of a theory. In other words, most experiments need a theory to be put in context. So, both experimental questions and answers need to be translated into the language of the given theory. This is not always an easy task.
To give an example: when you do General Relativity Theory (GRT), the theory determines not only the dynamics of the objects, but how your observations are going to look. If you assume that GRT is flawed, you have to correct not only the dynamics, but also what you expect to see with your measurements.
A related problem is the discrepancy in the Hubble constant as delivered by various measurements; it should be unique, but different measurement techniques give different and incompatible results. So, either we do not understand the measurement theory correctly, the measurements themselves are flawed, or - but very unlikely - the Hubble constant is not a well-defined unique concept, which would indicate new physics or at least a substantial reinterpretation of GRT. However, that last is the least likely - it is far more likely that the experiments themselves or the tools to evaluate the experiments are flawed somewhere. See also the apparent discrepancy of proton sizes depending on measurement technique: more careful measurements have now confirmed that proton size is consistent across measurement techniques.
Bottom line: updated theories can provide better interpretations for existing experiments which explain discrepancies, permit to resolve inconsistencies or suggest alternative experiments to be tried. A theory that just makes existing experiments look more inconsistent is worse than being wrong - it's completely pointless.
This is more an explanation than an answer.
For a theory to be valid it has to be able to explain all observed phenomena, even if only approximately. "Approximately" since we can't measure at an infinitely fine scale. So, the theory that the Earth's orbit is elliptical is valid, but only with certain assumptions and only at a certain scale of measurement. Perturbations occur, for example. But a "theory" that the earth's orbit is circular would not be valid, since observations contradict it.
However, one theory can be replaced by another if the new one provides better explanations for all observed phenomena, in particular those that weren't able to be made in the time-frame of the earlier theory. At one time the theory was that "atoms" were fundamental. That theory has been replaced since new measurements called it into doubt and newer theories (quarks...) provide better explanations. But the new theory still has to be able to explain older phenomena to be valid.
There are two ways (at least) that one theory can be considered "better" than another, and opens the possibility of one replacing the other. The first is that the new theory provides better (more accurate) explanations of existing phenomena, and especially a better way to predict what is likely to occur, even if only approximately (remember the importance of "scale" as above).
The second way that one theory might be considered superior to another is that if it is conceptually simpler. It has to pass the "accuracy" test, of course, but scientists prefer theories that are simpler and with fewer interacting elements.
Now, to the question at hand. If you can create a theory that can provide a model for existing phenomena but that doesn't need "anti-matter" as part of the explanation, then it might be simpler. It isn't a question of the "existence" of anti-matter, it is which theory can better explain the phenomena and, within those boundaries, which is simpler. Such a theory, if valid (see above) would make questions about the "existence" of anti-matter moot. But no such "theory" would be valid if it predicted things known not to be true. So, the answer to the question as you posed it, would be no.
And the new theory will only be known to be valid at a certain scale of observation and might be invalidated by new observations. The universe "is what it is". Theories are an attempt to explain it, not define it. The universe is "messy". Theories try to make sense of it to make the complexity understandable.