Vodacom is debiting my account daily leaving my account in negative state

I took a voucher advance with Vodacom/vodapay and my agreement was to pay it in 14days and I soo,but to my surprise vodacom is continuing debiting my account daily and since my account is empty all the declined transactions are charging me R8,50 three times a day ,my bank account is now in areas, I have log a complaint in the beginning of October until today my issue is not resolved a lady called *** she is not really helping me because as I speak she just say I'll respond but money is going out on my account everyday.she requested for prove I gave her my bank statement but she is not resolving nor responding.