Incorrectly billing

After numerous attempts to get Vodacom to change my debit order date finally they managed to get it right after 6 months of calling. This month they decide to debit my bank account the day before the end of the month and naturally there is no money in my account. The debit order bounces back and Vodacom charges me R100.00 for a R347.50 debit order. I explained the Nqobile in subscriber collections department that you cannot debit my account the day before month end because it falls on a weekend due to the fact that my employer does not pay me a day early because the last day of the month is on a weekend. This is ridiculous reasoning, why not take it the Monday after month end then? It took me 45 minutes to get through to somebody to assist me and being cut of 4 times, absolutely pathetic!!! I have requested the R100.00 be returned to me immediately, I then get told I need to wait 14 working days. I will now be putting a stop order in place with my bank and manually pay Vodacom every month. So sick of bad service.....