harassing for paid bill

i was admitted at netcare hospital on the 20/04/2015 and was see by Dr MAKGATHO, AT , medical aid did not pay requested i pay and get a refund from them, bill was settled but months later since December some rude lady has been harassing me requesting for payment as the account was handed over to the attorneys, two months of letters, sms and threatening calls i emailed Dr office and they apologized, and said it was never closed as paid , following days i get email and threatening letter from attorneys that claim was paid and forwarded them confirmation , but still today i have not received any feedback from Dr office or attorneys. angry and frustrated as i do not know if the matter has been settled or if im blacklisted for paid account