Do I have a case?

I was told by my supervisor that the day of my surgery would be covered under the first call off/doctor excuse or file fmla but don't worry about it that it would be covered, also that I had to use all vacation time before fmla would kick in, at that time I had two weeks left which can be broke up (which management nor shop steward knew) my surgery was on a Friday, off sat/sun vacation started that Monday until that Friday the problem is that my employee waited until I came back from vacation to now figure out how Friday would be covered supervisor is denying conversation and shop steward is saying he doesn't remember the conversation but also told me that he would prefer that the conversation not be bring up( I think fearing retaliation) I was denied fmla because it wasn't 3 or more days unpaid days off but I could have filed a different type of fmla and it would have been approved but their isn't a appeal process! My job could have just used a vacation day. I'm apart of a union