Phathetic service and systems

My grandmother's money was withdrawn at 7am 13 March 2021 while she was at home, went to the bank, waited for over 2 hours found their system were offline, and asked if what is the process for such incidents, there was no answer, went to the other branch got there still their systems where also offline however they called the HO and blocked the card, their feedback is that the case was not reported in time, now whose fault is it that their system was offline? please help i want my money back