Incredibly poor service

80 year old now living in UK with progressive disabilities, I have tried to get access to my account and also contact the bank with no success. I have even given power of attorney to a family member in SA which the bank refuses to recognise I can’t get through to anyone to help me with this problem and I have no access my pension now. My pension is paid into my FNB account I had the same locked out thing about 18 months ago and flew to Jhb to sort it out. There's a branch in the airport but it still took 3 visits until it was fixed. Now, with my progressive disabilities, I couldn't do that. I doubt I'd survive the journey. Communication with them is dependent on the code that the app throws out and i don’t receive the code I keep getting notifications about withdrawals that I'm not making. In any event I do need the account restored to me. And the bank is being extremely difficult to deal with.