Mellins i.Style a business not to be trusted

Mellins i.Style handed me over to Barretts & Associates who are debt collectors, in spite of my medical aid paying the balance of my bill within 3 weeks of me receiving my glasses. I had also signed a debit order authorising the Fourways Mall branch to take the balance owing if the medical aid failed to pay up within the specified time. Barretts & Associates insisted that I pay the R1 830 which according to them was owing, which I stupidly did, and now 6 weeks later my money has disappeared - ******. Mellins, very quick to accuse a client of non-payment but what does this say about their book keeping - or are they just *******?