Can't get rid of friend requests?

I have been getting friend requests from people that I've never been in game with and I can't delete them. Every time I accept one of these "random" requests, it's always some kind of spam thing that says something like "Hey, I was the guy that carried you a few games ago. I'm doing some boosting, you should come check out our website at [enter virus containing, spam link here]!!!!!!" If I hit deny, it says I've "deleted" the request, but it still sits there, even if I relog...

Sometimes I get friend requests from people I've played with and whether I accept or deny them, they go away, so it doesn't seem like it's a problem with friends in general.

Can a Rioter help please? Or someone with some knowledge about how to get rid of these things?

Thanks, -Viktor