Inconvenience to customer

My debit order date is the 20th of every month. If it falls on a Sunday, I get paid on a Sunday. Last month I got paid on a Monday the 20th. 1st for women debit my account the Friday before, leaving my account on a minus. I called to inform them of the inconvenience on the 22nd. Leaving me with a R200 plus bank charge. They advised me to send my bank statement. I did, and till this day I have not heard anything. Every time when I call to do follow up, my call gets cut