HELP!!! Trying to sell an account!

[pyrojunkie]

So this guy contacted me and we agreed on a price and that he would pay me first (glad we agreed on that). When i received the payment moments later i got and email from paypal:
"
A review of recent transactions indicates that you may have received an
unauthorized payment. This means that the PayPal account holder may not
have authorized the payment you received.

We would like to learn more about this transaction. Please log in to your
PayPal account and provide some information.

We strongly advise that you not ship the item until our investigation is
complete. If you have already shipped the item, please log in and let us
know where you shipped it.

We have placed a temporary hold on the funds until the investigation is
complete."

I got that... and my paypal account has been limited to where i cant spend receive or gift money. I had no limits on my paypal except for a sending one of 2k.
Please help!! (Btw the amount paid was 1000USD)