Urgh, that sounds horrid!

It is absolutely horrible to be treated badly in a rental situation, leaving you feeling unstable in your housing situation. 100x worse when it is a personal connection that has screwed you over.

Sounds as if you have done nothing wrong but have received the short end of the stick anyway. Absolutely sucks and I wish it was not the case. I don't know how some people can sleep at night when they pull things like such this, blatant deceit.

I don't have any advice but just wanted to say I am so sorry to hear of what you are going through. I agree with kelebek though. Doesn't sound like you owe him anything and there isn't really a way he can make you pay for things you don't owe. Maybe send him a calm, dot point email outlining your belief about the couch being clean or outlining your agreements prior to moving in concerning cleaning of the couch and also outlining dates and payments. Also, make a clear point that this is the end of things and you wont be discussing things any further.

All the best, you deserve a mighty big break to be coming your way soon