DISCOVERY HEALTH HAND OVER TO LEGAL

I was retrenched in September 2014. I was on Discovery medical aid. I owed them money as I had used the medical aid and owed them money. They call it a claw back. Just on R7k. I told them i will gladly pay it back. After many emails and calls i finally got a bank account to which to pay it back. I pay back R500-00 per month and have done so since Feb 2015 and kept to the arrangement. Last week I get a call from Vermaak ATTORNEYS that they had just received instruction from Discovery Health for money I owe them. I told them I have made arrangements to pay and kept to it. I told them I will not pay their legals fees as I had done as promised. How can they hand you over and claim legal fees if they are receiving their money.