Non ending accounts payment

I had a woolworths credit card which I believed to have paid off last year January, in October 2018 I was contacted by Hammond Pole attorney to pay the outstanding amount of about R1170, I verified it with Woolworths and their call center agents told me they cant help me anymore because the account has been handed over. I paid the account through their lawyers where I got proof that the account is settled but to my disappointment Woolworths has now sent me a notification that. I now owe the credit card and personal loan , both of which I have settled , and to add to my frustration is that Woolworths representatives says they cant help me , now I'm stuck with payment demands for accounts I have paid .