Vodacom want to Debit order and make you pay twice!

I have been a loyal vodacom customer with a premium handset and contract for the past 13 years with a debit order being processed every month without one single debit order bouncing back as there is ALWAYS money in my accounts, lucky me, I know. Since January however, Vodacom’s, AND ONLY VODACOMS debit orders have been bouncing, even though there is money in that account, all my other debit orders go off fine. In any case, it comes back as failed, and then a SMS says wait a few days and they will process it again, which they do, I am looking at my banks statements and proof of such, each month, a few days later, the debit order goes off again and its paid. This month, I am getting 5 phone calls a day and SMS’s like you won’t believe stating that I am in arrears and they will terminate my contract if I don’t pay, I go and check and I see, it’s been paid, every month, without fail. I call the accounts department today and they refuse to assist me, stating that I am in arrears and I must pay! and then dropping the call on me, multiple times, I have call recordings. all I want to do is send my proof of payments to someone so you can see that my account has been paid every month and set my account straight yet no such luck from this joke of a service provider. threatening to blacklist me for PAYING MY ACCOUNTS?!!?? I also want to add that I have had to login to pay the "penalty fee" of R100 now even though, the bounce was clearly their issue!