[Frozen]

Originally posted by Mourdor
Well, advice is kind of hard to give only knowing one side of the story.

Are you sure you gave him absolutely no reason, at all, so he began to act like that?

Another question, maybe he began to like you way too much as Mourdor said, maybe even fell in love, but having got no "response" or just indifference, became like that?

Right here:

...saying I've never been his friend and he only lied to me because he wanted something from me but I didn't understand what so he has no more reason to lie and say he's my firend.

Maybe he wanted you (no joke)

In your case I would still try to find out why his awful change of attitude, and bring a solution if possible, even keep being friends if there's a way for that to happen. But don't waste your energies in such a loser. I discard anyone who begins talking shit about me. But don't degrade yourself to his level either. I'd rather ignore him than beginning to insult him and say he's shit and stuff.

I hope this turns out for the best.