I am disgusted with Vodacom.

I have been calling about the same issue since last week and still has not been resolved ,I am now wasting my airtime and my work time. I am with Vodacom for more than 10 years.I have just taken out another contract. I paid for the sim card and installation at the store. I completed a form ans said that I can only be debited on the 25th of the month. A debit went off my account on the 22nd which was returned because I had no funds. The debit went of on the 25th no hiccups. I get phone messages all the time saying my account is in arrears because I have to pay for the debit order that was returned. I am disgusted with Vodacom.