Worst Service ever from Cell C's account department

I have been struggling with Cell C account department for more the a year already, first they said my contract is in arrears so I paid the outstanding amount with a very kind lady that explained everything to me in detail because I was paying my account VIA EFT so I gave her my banking details so they can change it to a debit order, Non the less the debit order did not go off as agreed now Cell C is wanting again money because the account centre does not log the information, the lady found me and I requested to speak to the manager the phone got hang up, today another lady phoned and said I see you did log an agreement and I don't even know what agreement so I said no I would like to speak to the manager and again the phone got hang up. I refuse to speak to anyone else beside the manager and no one can put the manager on the phone for me so again Cell C switched off my phone most terrible service ever and will not recommend them to anyone.