SIL’s birthday

Anon

Last year on my birthday (just before Christmas) my sister in law and my brother in law (husbands brother) did not acknowledge my birthday at all.. no happy birthday, nothing! Then out of the blue she has deleted me off her Facebook. I have no idea why these things happened as my husband and I haven’t done anything to merit this (I thought everything was great). My husband said he would talk to them about it but he never did! Now, we still have to play happy family because of my husbands parents, who have also not said anything about it to them. I wanted to say something but my husband said no, he will talk to them! Now I feel like too much time has passed to say anything. It’s my sister in laws birthday on the weekend and we are supposed to have dinner with them and get her something but I really don’t want to go or get her anything - we had spent quite a bit (like hundreds) on the both of them for Christmas before all this happened. What should I do?