My contractor did not pay final bill on quartz. Mechanics lien?

[Taryn Schettler]

I hired a contractor last year to do a kitchen remodel including him sub contracting another provider for counters.  He paid the down payment for the counters but did not pay the final bill of $1300.  I have since sold the home and I just got notification 15 months later that he did not pay and they are requesting payment or they will file a lien on my property (again that I no longer own).  What are my options here?  What should I do or who should I contact?  The property is in Iowa and the contractors are Nebraska based.  I have documentation of my payments to the contractor and the contract with the quartz provider that he was to sign but I also signed at the end.  I don't know if he actually ever signed the contract.