MTN Fourways Mall disgusting service

Today I had to accompany my elderly grandmother who had cancelled her Wi-Fi contract 5 months ago but yet her account is still being debited, upon arrival she was assisted by an *********** rep by the name of Senzo Mabunda, he did nothing to assist my grandmother instead said they don’t work with billing queries and gogo must call customer service, I asked him to call on her behalf since we have been coming here numerous amounts of time for the same thing,he refused , and further stated that we need to be assisted at the branch that the contract was taken at, which is shocking as it’s the same service provider and we should be assisted wherever we go, we eventually got assisted by the lady who has been assisting gogo since September,but till date nothing has been resolved ,everytime we have to come and state that her account has been debited and also have to go to the bank to have the amount reversed,Senzo even further stated that I’m causing a disturbance at the shop yet every month my grandmothers finances are disturbed by this matter, can you kindly please train your employees that a customer must be treated equally even if they no longer have a contract with you, but customer service has to come first