Missed payment

In August I took out a new co tract with Vodacom. Paid R105 in store for connection fee and agreed to a debit order on the 26th. The debit order went off and on the 3rd of October I received an SMS stating that I need to pay R100. I went to the Vodacom retailer and was told that it's an activation fee. I paid it in store that same day. I have proof that by the contract agreement I paid my account on time and that I never owed Vodacom but they actually went as far as listing it as a missed payment on credit buaro. After more that 5 years of not missing a payment. Please Vodacom get your documentation ready, I have been negatively affected by this and will consult my rights if it's not cleared from my name.