over charged!!!

at the begining of the month my debit order did not go through!every month it is +- R690 and this month was way more!im allowed to buy a maximum of R110 a month on my account and for some reason i was billed more than R200.i filled a complaint and made several calls to find out whats happening sothat i can pay my account befor my line gets blocked!no one could give me any answers!!!!!!at the end of the day,i cant pay my account because no one can tell me what the correct ammount is,my phone i going to get blocked and i will have to be responsible for any extra fees because of bad service and over charging me!!!