Harrasment for a paid account

I'm getting phone calls harassing me for an account i paid in 2013, THEY KEEP CALLING ME, SENDING ME SMSES, NOW THEY EVEN SMSING MY FAMILY! I will not pay the R11 000, you claim I owe you, I have settled the debt with MTN, and they told me its paid in full. YOU WILL NOT GET A PURPLE CENT FRM ME, YOU CAN SMS AS MUCH AS YOU WANT, I DON'T GIVE A F..K !!!! YOU CAN GOT TO H..L FOR ALL I CARE , GIVE ME A DETAILED STATEMENT FOR THAT R11 000!!!!!