I have a problem with the billing

I have a problem with the billing . So September and August we paid for the 2 month and October arrived the 15th which we have to pay every month on that 15th so as I wanted to pay and open up the app I see a bill of R R1138 i then phoned in for assistance they told me to sent proof of statement that I payed the 2 month in a email all I get back is an email of they will fix it back its still not fixed and I have phoned multiple time and it’s still not fix because I need to work on my lap top