Negative credit record because of Lewis store's fault

I bought a few household items om account from Lewis the end of last year.Each month my debit orders went off as promised.Come December my; payments went off earlier than signed for as per contract but I accepted the earlier debit orders.I went to the my financial institution to apply for a personal loan as I was planning on expanding our livestock flock.Regrettably I was informed that there is an amount outstanding on my Lewis account and because of that my loan was unsuccessful.I drove to my closest Lewis store at which I also bought from and demanded an explanation for the "outstanding" amount.I have even showed the manager the payments on my bank statements....She made a few calls to the head office but nobody was able to help!The manager informed me that she will follow up and phone me back the following day; which was today; but failed to do so....I'm fuming because of this as this matter influences my credit record negatively negatively!I demand this matter fixed ASAP and have my credit record restored to how it was before this mess.....made by someone tyhat I feel is ***********. How come Lewis stores never phoned me to ask me about an outstanding amount on the account??