BAD ACCOUnt SERVICE

I have been trying to resolve debit order issues and my account balances with Cell C for 3 months now. Their debit orders are not going off, but now they phone me and lock my account because I'm in 'arrears' but they havent been taking my money. Worst of all, I am valid for upgrade this month and now they claim I cannot until the account is up to date. I dont want to eft the money for fear it then goes off and then i have to fight to get my money back. I have been with Cell C for 15 years and this is the service I get.