Discovery is lying about unpaid account

I was retrenched and after several months, was unable to afford my medical aid. It was cancelled and Discovery then wanted the difference in my savings. I spoke to a consultant in December and let them know that I would be paying small amounts as I was only starting my new job in January 2025. I was informed that if I didn't pay within a short timeframe, that I would be handed over. Despite making continued regular payments, I was handed over. The entire account was paid in full in April this year. I am still being harassed by two different agencies for the same account. Both insist that I have only made one payment and there is still a debt outstanding to Discovery. This is simply not true. I have been in regular contact with *** and they have acknowledged that I have paid the full amount and have requested removal from ITC. However, they state that I am still liable for charges related to being handed over, as I did not make an arrangement for a payment plan. I did ask for a payment plan in December, and I was told this was not possible. I struggle to get the names of the debt collectors as I have poor hearing, and to date, I have received no email notification - only phonecalls. Please stop harassing me. It was ********* to have handed me over when I was making regular payments.