cell c has given me nothing but trouble

i was ****** in november and got a contract as i needed a phone asap because my student account bank account card was ****** i opened a new account as i needed my salary to rather go into that account i went to cell c with my bank statement for my student account and my new acc told them they need to direct debit new acc not old one. they confirmed it wouldnt signed my contract for the phone i didnt want as they didnt have any stock in samsungs at all and told me they dont know how long i must wait. 5 days later conection fee went off student acc in nov i went to store told them and took banking details to them and they said they changed it. my sim conection went through coz still had money in acc but couldnt use it as card was gone. end of the month dd went out wrong acc i went back with bank charges and got a cold shoulder and told i have to pay bank charges. still today they still dd in wrong acc i spoke to managers in call center aswell as people in store i have 615 rand in bank charges and my phone is barred due to non payment and my credit record has been affected because of there mess up. cell c called me to apologise and tell me they will credit 100 rand is this fair?