Vechile and asset finance problems

I've been with standard bank for almost 10 years now, and in the last couple of months had the worst experience with them, with card problems to vechile and asset finance problems and this is unacceptable in my opinion they attract customers but their whole structure cant support all their clients needs and complaint. The problem i recently have with the asset and finance department is, my vechile finance is payed every month via debit order the 1st of every month, my account is up to date and can be confirmed with my transactions history but they kept phoning me and sending me sms's about payment in arrear and i ignored this because i made a payment. When i logged into my clear score my credit score dropped 17 points and standard bank logged q payment in arears agianst my name after phoning their asset and finance department they informed me they have a technical problem but how is this fair to affect my credit score? After complaining about this they assured me it wont affect my credit score as the porblem is on their side? But its already showing on my clear score and they cant give me a rational explanation or what is going to happen about my credit score that has been negatively affected how is this acceptable??? They never send me an email informing me that they received the payment like a asked i want it in writing that the problem is on their side and that this wont happen the next month... how is this acceptable a simple apology wont do!! They affected my credit score with a technical problem from their side !!!!