Very poor service!

Very poor service! Spoke to 2 consultants last week asking for the paid-up letter, they said I owe R90 more. They both said they will come back to me and send me the statement, still waiting for my statement. Today I spoke to another one, now i owe R700+. How the hell do i owe R700+ today? whereas last week i was owing R90. I settled my account on the 25th and now they giving me stories. I was owing R588 and paid R600 on the 25th of May. Now i owe more! Bunch of ******!