Credit Score affected by Vodacom

I've had a cellphone contract with Vodacom for almost 3 years now and I've never missed any payments since we arranged for a Debit order payment. This year in 2021 August I received a phone call that my account has been handed over and I'm in areas, to my surprise they stopped Debiting my account and there was no communication from their side as to why they stopped, no email, no phone call. Instead I took it upon myself to call them and find out what happened and their Consultants also don't know including their Collections department.... Now my Credit Score has been affected due to their incompetence and negligence. I have arranged to settle this contract and I have made full payment but they are telling me that I can't get a settlement letter or statement to show that my account has been paid up. I'm so disappointed with the service from Vodacom and I will Never Ever sign up another contract with them.... I have fullfilled my responsibility as a client to make sure there are funds available in my account every month and they failed as a service provider to Debit my account and now I have a Bad credit record because of Vodacom. Now I can't get a home Loan because of this.