(Paid) Debt caused by error from service provider

England.

Last year I missed a payment with the water provider of my house. I had just bought the property, didn't have notifications setup, and I just realised I had missed it when it appeared on my credit score.

I contacted them, paid it right away, and asked for a direct debit (it's not possible to set it on the website for some reason). They said yes and that it would be set for next year (so, 2025) since it was already paid now for the year.

I thought that was it. Well this year, the same thing happened again. I knew I had setup a payment plan so I wasn't worried about it since all of my bills come through direct debit, I'm not someone who ever misses a payment. But again I see it on my credit score. I thought what the heck, and went to check my records and I have them in writing saying they were setting it up.

I paid it immediately and talked to them, it's been a week of back and forth since their CS is terrible, but I want them to either remove it as a debt notice, or add a correction of some sort. They confirmed that they failed to create the direct debit I'd authorise and it was a mistake on their part, but now they say they can't do anything without "knowing how this affects my credit score". Well I sent them a copy of the message, and how it appears on the credit score, and the date I received the notification. But they're dragging their feet.

Do I have any recourse here? Or do I just have to accept that this will be in my file for six years?