I continue to receive threatening letters from Transworld Systems in spite of the facts that:1. The debt was paid by check which was cashed on XXXX XXXX, 2015 ; 2. I telephoned Transworld Systems on XXXX XXXX, 2015 at XXXX PST and informed XXXX XXXX that the debt had been paid. She assured me the threatening letters would stop but I received yet another on XXXX XXXX, 2015.