paying for zero service

MTN refuses to allocate data for the month of May because I paid on 2nd. I paid extra so that the account can be reinstated and data be given for this month. Attached is my proof of payment etc. where I’ve paid more late fees. Essentially I am paying for zero service. Upon phoning MTN customer care and technical support line I was told that because the payment was made on the 2nd I can only receive data for the month of June, Please explain how this is possible if I’ve made payment for the month of May. This is a month to month account and I have paid around this date before and nothing like this has occurred