Debit order date

My husband changed jobs and is not paid on the last day of the month, he has called Cell C numerous times to advise them to move the debit order date and they have not causing us to be charged for return debits. When we called this morning we where informed by a very rude call center agent that they can only debit on the 30th and than again on the 15th, they refuse to debit on the 1st. What kind of company cannot debit on the 1st. So they will debit before his salary is paid take it or leave it. Well we wish we could leave it but unfortunately we are contractually bound for another year. What shocking so called service.