Bad service and incompetancy!

Edgars closed their shop in Oudtshoorn.Ever since they closed they phone me each and every day about my account.I pay every month the full amount by EFT,even mailed them the proof but they keep on phoning and harasses me.I am sick of them. My name is A S Smit Acc no : ***74 4844. They said that they will rectify my account and they even acknowledge that they reveived it but today I received a sms to tell me that I have not paid. If you cannot help me I will go to my lawyer to open a harrasment case. My phone no : ***.