Urgent Question, Someone Help!!

Hey guys,

So I live in Canada and purchased a Early 2011 Macbook Air off Kijiji for a really good price. Drove almost 45 minutes to get the laptop. Before agreeing to buy it, I asked all questions such as: "is anything wrong with it?", "is the battery working fine?", "any damage?", etc... To which the seller replied in all positives. He indicated that nothing was wrong with the air. He also mentioned it is covered under Apple Care until the end of April. I agreed to buy it, drove there gave him cash and drove home.

I started noticing problems such as video freezing and an overall lagging. So I decided to go to the Apple Store and get it checked out since it was "covered" under warranty still. The apple tech notices problems with it (charing port not working, freezing, etc.) and he then goes on to tell me that earlier this year (January) it was at the Apple Store in BUFFALO. He then says it was deemed "Water damaged"... he took it to the back and open it up to make sure. He then came out and told me warranty is void since it is water damaged and that if they were to repair it, they would bill me like a $540 bill... I said no thanks and went home.

The seller told me nothing about water damage or anything! He even gave me a "replacement" charger of cheap quality. I contacted him and now he won't even answer my calls or my text messages. However, I have all of his emails and text conversations saved. I also know where he lives.

PS. Now the macbook air does not even charge anymore after the apple tech opened it up! What can be done about this? Please help me out.

Thanks!