Suspended services three times in one week on paid up connection

I am not impressed. We paid our subscription on the 14th December 2018 in full and the following is happening: On 21 December we got an sms informing us that our account is suspended due to non-payment. After long telephone calls and emails with proof of payment, the service was reconnected. On Wednesday 27 Dec the same story, but bill with connection fee is higher than Friday's! After en email to Zanele (a very sharp and helpful lady) the service was reconnected. This morning the same sms, with an even higher outstanding amount! This is poor service and everytime its my airtime and data that is used to rectify their mistakes!