Handling of my Account

I had a rather big account with Drs Du Buisson when I had a back operation and had complications which resulted in huge medical bills. According to my record I paid them up in full. Got an SMS stating that I still balance outstanding. When i phoned the number I was told I was handed over and that is additional cost. According to my records they are paid in full and must sort out the fees with the company they told to collect the money which i wasn't even aware off. I see this matter as closed as my balance with them is Zero. The last statement I got from them was dated 22 November for R188.70 and that according to me was paid in full on the 8th December.