Double charges and no clear explanation! clear duplication on the part of the service provider

I have been a customer with VOX since February 2020 without any issues. This year as I was moving units the service immediately deteriorated in terms of billing. I informed them I wanted to move my service to another unit to which the explanation was dismal and the transfer absolutely unbelievable in terms of lack of clarity. After explaining to them that I was not cancelling my service but moving I was then told I would have to pay for the month of March. I paid the invoice amount. I then raised the issue that my service by the 10th of March my service was still not connected as an issue on the part of VOX and VUMATEL and requested that I recieve a prorata fee because for 10 days I did not have service and therefore cant pay for what I didnt have. I was told that this is something that cannot be done and I have to pay the full amount. I paid the full amount quite unhappily because to me that does not make sense. The explanation was again unclear. today after making a payment of R649 on the 17th and R719 for the month of April as per invoice I was informed I had shortpaid and still owed R621 for something that is unclear. I have not been profered with an explanation as to why I have 2 amounts due for the month of April when I requested the account be cancelled at the previous unit in March. I dont know what kind of institution is being run but this constitutes a false charge that goes against the agreement I have with the service provider.