Unable to close bank account

Recently I moved overseas and had to keep my account open during the move. Now after multiple emails with no response and several unhelpful phone I still am unable to close the account. After having been with standard bank for 15+ years I would expect better service than this. How hard can it be to close a bank account? Every month I am getting bank charges and interest fees on my account. I don't know what to try anymore, it's absolutely ridiculous and unprofessional!