Cell C failed to correct details after 3 tries!

In May 2015 I opened an account with Cell C, filled in a debit order form & gave my FNB banking details. I was told the joining fee & package fee will go off end of June. End of June my debit order didn't go through. I phoned to ask what the problem was: they had STANDARD BANK details. I gave my FNB banking details (AGAIN) & was told that all the relevant fees will go off end of July. 3 August, no debit order has gone off. I emailed the Greenstone branch to query the delay. I got no response. 5 August I received an SMS stating my account is in arrears. I called the customer help line to ask a THIRD time what the problem was: they STILL HAD STANDARD BANK DETAILS! I EMAILED my details to the operator. Not getting a response, I phoned AGAIN. My details were still not changed. I gave my FNB details AGAIN(4th time) & was told the debit order will go off the 6th. HOW did Cell C get Standard Bank details if I did not GIVE THEM STANDARD BANK details on the form & FAILED to change it THREE times!? I didn't want to complain, but this is unacceptable. Now I have to pay a big lump sum of outstanding amounts because of Cell C's *********** staff. I am regretting the move I made to Cell C!