When you say you "couldn't" unsubsribe, please provide more details that will help us find, duplicate, and hopefully resolve the problem:
• Did you receive any error messages? if yes, what were they (please copy and paste the entire message, screenshots are best)?
• What were the exact steps...
Why do you want to "get rid" of them?
Is it an issue of being subscribed to them? If you're not subscribed to them, you may never even come across them again, which is kinda like getting rid of them. You can go into your subscriptions and edit the settings in pretty fine detail.