No managers available in call center

I changed my account from a savings to a cheque account and I was told there was no overdraft facility and if there were not enough funds in my account, the debit would bounce and I would have to pay an admin charge. I was fine with this because there’s a debit charge I’m avoiding due to a dispute. Saturday the debit went off and my account went into overdraft by thousands. I called the expensive 086 number and was told that nothing could be done until after midnight. I called after midnight and was told nothing could be done until 24hours had passed and that no managers were on duty until 6am. I called at 8:30am and was told there were still no managers. I called after 24 hours and nothing could be done and I requested a manager. I was advised none were available and I left my number and have still not received a callback. I have severe depression and am now left almost bankrupt which certainly does not help.