Worst experience with banking was Barclays legal department making a horlicks of registering lasting powers of attorney. After my debit card was rejected at the till I discovered that instead of registering contingency LPOA attorneys they decided I was dead so my cards were all useless. Tried to sign into online banking but the accounts no longer existed and telephones wouldn't talk to me as I was dead and therefore presumably phoning from 'another place'.
Took two weeks to sort out. Local branch manager immediately advanced a grand in cash interest free so I could pay for my shopping while it was being sorted and the area personal banking person took up the cudgels on my behalf (knew her anyway as her now late mum and Mrs HGBs late mum were deteriorating together). The Lord knows what would happen now as they closed Barclays branches in Guiseley, Rawdon, Yeadon, Ilkley, Otley, Shipley etc.... (there is apparently a self-service Barclays in Leeds and one in Harrogate if I fancy the ten day camel rides to get there...) If for any reason I am unable to do online banking in the future I will like everyone else truly be up the creek