Very bad service Rcs

I have been dealing with bad service from a company called Rcs. The core business rcs cards and loans. I have a small loan with rcs and discovered rcs was doing double debit orders on my bank accounts. I immediately made contact and there reason was admin error Totally unacceptable it was discovered that 2 mandates were activate on my account. I later noticed the following month they did not procces my debit order. I again made contact and once again admin error. I have now discovered I have a missed payment on my credit report due to there incompetence. I want that removed and to make potential customers aware