MTN Useless customer Care

I have a contract phone with MTN, and they load data monthly. For the past month I cannot use this data if I want to send/receive whatsap they hang. I have reported the problem last month, they keep telling me that they will restart my line and to this day I still cannot use their data and yet I am being billed monthly for a service that I cannot use. I asked the customer service if I can speak to their supervisor to this day I am still waiting and sitting with the service I cannot use and yet monthly my account is being debited. MTN service is stinking.