I have a paper accepted at X conference. It has a very expensive registration fee which I was told would be paid by my advisor. But now they are not going to pay.
It was an abstract paper and they will be having a book of abstracts, but I'm sure if I don't pay my abstract will not be there.
I think this will depend on conference policy, but in general if you have to pay even though being a presenter (some conferences will waive the fee if you do a presentation, but that doesn't seem to be the case here), not paying the fee means they are going to cancel your presentation. Most often, they communicate this when confirming that your abstract has been accepted (e.g. "If the registration fee is not payed until the ..., your submission cannot be considered.")
What you could try, though, is contacting the conference organizers and explain your situation - maybe they will make an exception and allow you to attend (and present) without paying because of your special circumstances. It doesn't hurt to try.
