Cell C bad service

Hi Cell C has the worst customer service to date. I have been calling them all year round to sort out my debit order date. My debit order date is on the 6th of each month but start deducting on the 1st of each month. When i query the dates, they tell me on the 6th. I have asked that their supervisor or manager must phone me because when you ask, they are always busy or out and never return my calls. AS it is on the 1st it does not go through as my salary paid in on the 3rd. this is one customer who is going to cancel his contract when it expires in March. Goodluck Cell C trying to get 10 million new customers.