Please correct the annual payment due in March

Some year ago I subscribed to the annual payment (i.e. you get one month free). Two years ago the trouble started. The payment wasn't reflected in March. I queried it and the consultant said the system didn't allocate the payment. From that point onwards the payment was due in April (after the increase). I paid the additional one month (and the reconnection fee).

Last year it was corrected manually, but I did ask that the payment had to be defaulted to March, this obviously meant that I was due for a credit for one month. This year I checked in March and the system said payment due in March was R 3520 , I wondered what happened to the credit for one month. I paid that. But on the 12th of March, no invoice and the system said I was due for R209 on the 12th of April (which is exactly the difference between the old rates and the new rates).

Kindly correct this mess. I am due for an annual payment in March. So you are going to have to credit me for a month. Please let it not happen again.