MBD Sokutions are ***********

I was handed over to MBD solutions by GEMS. I was handed over by GEMS whereas I had already started paying GEMS the money I was owing them. So when MBD started calling me, GEMS told me to pay MBD. I continued paying for the debt unaware that I didn't change the banking details to MBD, but they continued sending me statement indicating my balance which showed they were receiving the payments. The problem started when I paid off the balance of R2135, 70 in January 2017. I went to their offices to give them proof of payment , I discovered that i was still paying GEMS but they were receiving money from GEMS and i was told by Mr Gabriel Manana that my records will be updated. They call me everyday demandingR2135.70. I sent emails with proof to Mr Manana and other people at MBD but I still receive calls and emails demanding me to pay. They are ***********, I really don't know what to do know