Waiting on paid up letter

I had a woolworths account that was handed over to MBD and I finished paying it December 2025 already. They keep on sending me messages and phoning me about an outstanding amount on the account. I accidentally made one payment of R1000 on the 16th of November last year to Woolworths, as they are one of my beneficiaries on my bank app, and not to MBD. I have sent the proof of payment 6 times now to MBD and phone them every week, just to explain the whole story again. I am still waiting on my paid up letter as I have no outstanding amount on my Woolworths account. Please can you sort this out and stop calling and sending messages. I hope this is the last time I have to ask for my paid up letter.