Can the seller’s wife do anything since I am paying her just not as fast as she would like?

I bought a truck with the terms being that when the seller’s house sold I would pay them out of my commission. We had an offer on the house. In meantime truck clutch broker cost us 750.00, we also had to repair heater 100.00 do a few other things until the truck was drivable around 1,100.00. We know that when you purchase a used truck things happen. In December the sellers wife wanted to come pick the truck up from us because I had not made a payment we never talked about payments just when ever their house sold I would pay them out of my commission, the deal fell out on December 23rd I said if you want to reimburse us for what we put in the truck then you can come and get it otherwise lets work out a payment plan and then the balance of truck will be paid off when the house sells we got another offer on house 10 days later. I said I could pay her 200 a paycheck 2 x a month for awhile I was working part time then. In may my job ended but prior to that She leased out the house that I was trying to sell and told the tenant not to show the house, but was paying me 200 a month from the rents she collected. I told her around May 14th that I cannot make any more payments after the one on the 17th till the house sells I only owe her 800.00. She has a 6-month lease on the home and 5 months remaining so I said that she can keep my portion of the rent as payment for the balance of the truck. She said she is taking the truck back keep in mind I have a bill of sale and the title in our name.