I sold my 2008 GX470 to Putnam Lexus 2 weeks ago a...

I sold my 2008 GX470 to Putnam Lexus 2 weeks ago and got a check for $15,000 of which we agreed upon. I deposited the check on Dec.17th. I just received notice that the check is being returned unpaid and my account is being charge a $10.00 fee.
I didn't have a problem when I sold my Toyota to 101. I got a check before I left. Putnam made we wait 3 days and now the check has been returned no good.
Whats going on at Putnam? Are they having financial problems? They have had my Lexus 10 days and I have not been paid??