This is a company called Convergent Outsourcing. They are a collections company. They are based somewhere in Texas but now they have local area codes to call from.
You are absolutely correct. The debt collector is Convergent Outsourcing, Inc.
(They actually answer the phone with the company name). They are located at
10750 Hammerly Blvd in Houston, TX but they purchase local phone cards in order to look ligitimate. These folks are not the original debt collector, but they bought the papers to your debt trying to collect (often at 2-20%) on the dollar to get their money back from the paper they purchased about you. Hope this helps.