Paid up Account

Please assist me my foschini account was handed over to HTN attorney and last year around April i paid up my account and emailed proof of payment and they send me paid up letter. But to my surprise im still getting sms and phone calls from htn attorneys every month to say that i need to pay my account. I have send proof of payment and paid up letter several times but still im getting sms and phone calls. In May i got a call again from HTN attorneys call center the guy who helped me on that day he said to me that it shows that i have paid up my account and the is a duplicate account under my name so he promised to sort it out for me but it looks like he did not attend to the matter because im still getting sms and phone calls. I feel so harassed because most of them they dont even talk to me properly.