CELL C REFUND

I've been with cell c for many many years, my debit order date is on the 26th of each month and i asked them to shift it to the 7th of every month now i have two debit order dates, i tried to fix it again and nothing happened so every month cell c debits more than they should, sometimes they'll go into my account and take money randomly like last month i paid them a fee of 1400 and they still took money from my account twice, i phoned and did a follow up they gave me a reference and said they'll contact me within two days, I'm still waiting for cell c to refund me all the extra money they took and it's not the first time that something like this is happening to me,