FNB not a bank to bank with

This bank is useless. I'm in the process of buying a new house. FNB said that I should move to them to get a better interest rate. When I go ahead with opening all my current accounts that I have they tell me that I do not qualify for a Credit account. According to them my credit score is not good. I've never missed a payments on loans or any accounts and had a credit check done as I'm in the process of purchasing a new home with no issues.

Why would anyone move to this bank and loose benefits of the current bank that you are banking with.