Account settled in 2018 but getting calls from debt collector

My Foschini account was handed over to Easton Berry for collection and I paid them in full in Aug 2018 and now I'm bombarded with calls from DMC for the very same account saying that the account has been handed over to them for collection and the is a balance of R7000.. and they adement that the account was not settled ......what happened to the payments I was making to Eastonberry????? Do I need to go to the ombuds to get this sorted????/