What a mess!!!

This is my second round of complaints against Fedhealth and their affiliated debt collection company. I have ALLWAYS been a good customer and payer to the Fedhealth medical aid scheme. I left the scheme about three years ago and all of a sudden (after three years) I get these phone calls stating that I owe them R544? I queried the amount but still proceeded to pay the amount and question. Now I still get these calls from Fedhealth, harassing me about the payment! Come on Fedhealth, this is getting to me now!!!! I would actually like you to pay me the R544 back and clear your accounts once and for all! Stop harassing me, check your accounts, the monies has been paid!!!!