For my thesis, I did some programming for a project. My supervisor seemed to be very happy with the results when I was there and promised I was going to be in the publication. Problems started when I graduated and moved abroad. My supervisor said they couldn't replicate my results and started pushing me to continue into the project. I left all my scripts properly organized with README files and was available to answer emails and connect remotely to do minor fixes, but I was already fully dedicated to my masters and didn't have time to do extensive extra programming. Indeed, I was doing field work and didn't have access to computers for most of the time. After almost a month in which I was out of reach, I checked my email and found a communication claiming I have stalled the whole project and lead to its cancellation. I let things pass for almost two years, not having much contact with my then coworkers or supervisor, and just yesterday found the paper was indeed submitted around six months after that final communication and taken into publication! And I'm in the acknowledgements albeit for a menial task that anyone could do in a couple of hours!
I can't be sure if there was misappropriation of my work since the code of the project hasn't been published. They might have rewritten the code, but they might have also indeed used MY code or parts of it. Unfortunately, I don't have a copy of my work, since I was doing everything remotely in the server and I now fear I wouldn't be able to substantiate my allegation to the editors in case they ask for prove to my claims (I know, I should have kept a copy for myself, but I never expected this to happen at all...).
I noticed some red flags before leaving but didn't think they were of real concern. My supervisor seemed to be resented at me leaving instead of staying in his lab. Although my supervisor is very good in his field, I didn't like the overall way in which he treated us, his students -- he is the kind of supervisor that would yell and call you stupid in front of your colleagues –. This is one of the reasons why I decided to leave the lab and even change field. I don't know if this affected his intention to include me as an author, but in any case, I think they should have informed me I was going to be mentioned in the paper, and they didn't.
Is this among the normal things that happened in academia? Should I tell the editors either they include me as author or they drop any mention of me in the acknowledgements? Also, among the authors are other students for whom I have real appreciation and I don't want to spoil their names in their first publication. Should I let things just pass and be forgotten? (The paper has been published already for more than a year and haven't been cited once. -In my opinion it's a good paper, but not a breakthrough). What would be the normal thing to do in academia?