In july 2000 we wrote a bill of sale using (PC Attorney) software to sell a small trailer for $900.00 with a down payment of $200.00 and the remainder to be paid periodically, no specific on how often. Since February 2001 there have not been any payments even though they still owe $300.00. We have tried contacting the person who bought the trailer but she does not return our calls. What are our options? We've given them all the time we care to give. We live in Massachusetts.