I don't want to accept gifts from my mother and sisters in law.

They were against my relationship with my SO right from the start and tried to make him break up with me for years by brainwashing him with lies and made up stories. Thankfully he loved me enough to decide he wanted to be with me despite the drama. We got married against their will. We've been married for 5.5 years now and throughout all these years, they never tried to have a relationship with me. Not only that, they did a lot of things to hurt my feelings when we met. But for the most part, they act as if I don't exist. We live in different countries so it's not very awkward because we're never required to meet. We don't talk. We don't interact. We live completely separate lives. 
But now that we're having a baby, they are getting us gifts for the baby. I would appreciate so much if they had been nice all along but apparently it's not the case. I'm afraid they are trying to have a relationship with my son, which is my biggest fear. I don't want my son to be near people like that. It would break my heart... 😢
Any advice?