Incorrect payment submission causing bad credit score

I launched a complaint with them regarding their listing on my credit profile stating that I missed two payments. However this is incorrect as my payments is going off via a debit order and is not in arrears. Their actions have a DIRECT impact on my credit score which is affecting my daily living. I forwarded a complaint letter to them but to date have not received any response. Their call center is useless as they will "escalate" my query - but still have not received any feedback regarding this. It would be so great if someone could assist me - but I am not hopeful.