Why do I keep failing Metro Bank’s security checks?

The reader hopes to resolve this problem without having to schlep 100 miles to her nearest Metro Bank. Photograph: Christopher Thomond/The Guardian

I have an Isa with Metro Bank that I have had for 15 years or more. I moved house a few years ago and have recently been trying to update my address with the bank.

My problem is, I keep failing its security checks. During my frequent calls, I am asked numerous questions and passed from pillar to post. I had to complete a validation process, which I failed, but Metro refused to tell me why.