Edgars & Nimble Group

I paid my Edgars account last year October in full ,my balanced was R0.00 account closed . All of a sudden I'm getting phone calls and sms from a company Nimble Group my Edgars account was sold to them . According to them I still owed Edgars money, after how many phone calls, sended my slip where I did paid my account up with nothing outstanding. Now this shows on my credit profile, and the simple answer from Nimble Group sorry Edgars needs to get back to us . If you phone Edgars sorry nothing outstanding shows on our systems......this is ridiculous