Vodacom get you facts straight!

I have my contract with Vodacom for about 20 years now, renewing every 24 months, and have a debit order going off my bank account every month without fail. In May my debit order went off as usual but now I am getting sms's telling me my debit order was rejected. I checked my account to make sure this did not happen and then called Vodacom. They apologized and said it is an error on their behalf and will rectify it however I am now getting calls from them with a voice message telling me to pay my account. This is absolute nonsense and harassment and Vodacom need to sort this out otherwise I will seriously take my business elsewhere and lay a charge against them for false accusation.......