Paying double monthly fees for 1st month subscription

I fitted a unit in on 1st September 2017 my monthly fees is R229 on the 2nd October I was debited R458 which I was not told about the debit was returned to my account and I got charge R115 service fees for the bank I contacted the accounts dept whom told me I was only supposed to be debited on the 1st November for the 2 month of rental and they will correct it on the 15 October I was debited R458 again and because of insufficient funds the debit was returned,I than contacted the accounts dept again via email but no response I than called them and was promised the same they will correct it ,on the 2nd of November I was debited R687 it was returned again of insufficient funds they never information me about the amounts and arrangement on the 6 November I call accounts again and was told I have 2 accounts and they will cancel the one cose I only have 1 vehicle fitted I than got a call from the accounts supervisor that was very rude and told me they systems is a pro rata basis where the 1st month I must pay for September and October I told her I was not informed bout this agreement and she said she will play the fone recording and call me back but didn't called me back Netstar is a *******ed company that has unprofessional staff my fees in bank charges is R345 which I should not be liable for they messed up and they blaming me for it please help me to get out of this mess who can i contact