Incorrect credit score, and incorrect missed payments

I don't even want to give this company a 1 star rating as it is not worth it. They have incorrectly submitted 2 months of missed payment and late payment on my husbands credit record. We have the statements and the debit order payments to prove those 2 payments were on time. No one can give me any answers, despite calling twice, and emailing a number of times. A credit score is very important. Why is such a simple mistake, not being Ammended? 2 enquiries have been closed without the issue being resolved. Very unorganized. Absolutely gobsmacked by the treatment or lack there, of that we have been given