First Data

Signed up with this company, business transactions with/thru them worst at best. I called after attempting to use their services for 3 mos. They told me it would cost $2300 to terminate before the end of the contract May 2014. I returned their machine return receipt by the USPS and have it. I closed my doors with the business 1 May 2014, and closed my business accounts 30 June 2014. Now I am getting mailing notices that they have attempted to collect another $37.94 after closing the account. Now they say this is a non-cancelable contract? I don't think so, I found this website, not sure if anyone else has found or used it, have entered info but have had no luck in sending.
http://www.classadvocate.com/classaction.php?id=1573