500fastcash.com I had gotten a $150.00 from 500fastcash.com in December 2010. I have paid this loan back and just yesterday I recieved a phone call from some lawyer telling me that I had two hours to come up with $35 Internet

I had recieved a loan from 500fastcash.com in December 2010 and I have paid them back for my $150.00 loan. On 8/18/2011 I had gotten a phone from a Ryan Johnson telling me that I had only two hours to come up with $351.00 or he will file court papers and take my SSD away from me for one year. I have the proof that I paid 500fastcash.com back because it is on my bank statements and in my checking account register it also shows how much each withdrawl this company made to pay off this loan. The first loan repayment was sent to them from the checking the loan was deposited to, all other payments to this company was withdrawn from my new checking account. How can I be at fault if their creditor didn't give them the money that they withdrew from my checking account? Can they legally garnish my SSD for one year? SSD is my only source of income and they new that plus it's how I pay my bills and how I pay my rent.