Paypal sending to collection for 43$

[Bruiser]

Hi,i'm from Canada
Last december (December 8th), someone i don't know sended 1500 uk pounds in my account, i don't know this person, didn't even sold something with my paypal account.
I immediately called paypal to tell them something is wrong, there is money that ame in my account that doesn't belong to me, so send this back to the owner, i don't know what's going on, and i don't know this person. The paypal girl told me it was probably a fraud attempt, somthong like this, so she say i'm going to transfer this case to the correct department and have all this setteled, it can take up to 7 days she told me.
10 days later, same ****, money still there, 20 days later, the rollover the transaction, but ask me for some do***ents, like proff of adress etc... and guess what they leave my balance negative of 43 US dollars, (Commission fees) now i got limited account, and need to send do***ents AND the 43$ us, i sended an email stating that i don't need to pay this, since it was a fraud attempt to my account, they don't mail back and on monday feb 11 NCO financial services start to call me to claim the 43$. SInce Monday, they call me 4 to 6 times a day starting at 8 AM t'ill 8 PM.
I explained them the case, they tell me that paypal ased them to take care of the case.

ANYBODY can help me with this, anny suggestions?