You don't need to give them any card details or real information, you don't even need to use their launcher to play the games. It's fine not to like them but don't put down people who just want to play a free game!
I think you're using the service wrong if that's the state you're ending up in afterwards.
Anyway, anything to do with them should be tagged with [Epic] so if your Lemmy client supports it then you can just filter/block all posts containing that string and never be bothered by them again!