Cell C giving me problems with sim swap

I have been requesting for a sim swap since last week thursday, it is now Monday! when i first called in, i was told it is unsuccessful because i was owing R99 for April, which i paid same day via easypay. i then passed by a Cell C store and i was told with easy pay, i need not fax the receipt. I kept calling and they were saying that the payment doesn't reflect till i went to another cell c store where they faxed the receipt and also called the center to unblock me. which was successful said the sales man. Sunday when i called in i was told that the dept that do sim swap only work on weekdays. I then called in Monday morning and i was told that the payment was put in for May, meaning i'm still owing for April. My monthly installments debits on the 30, meaning my May installment is still to be debited. So how come they put it in for May when their system should automatically put it in for April? i'm now told i should pay for April before they can do the sim swap. I need my number to be swapped immediately hence i made means to pay the credit immediately when i was told about it.I don't understand why i can not get my number when the mistake was done on their side