FNB is a disgrace

My mum who is 73 years old and a pensioner and i am currently unemployed who relies on her social grant that goes into an FNB zero account. For the past 3 days she is unable to access her account to put electricity. We have been to the branch to update her information and they said that she will be able too use the card in 2 to 24 hours but it has now gone 3 days and still she cannot make use off her card. This is really utter nonsense that a person off old age must suffer like this because FNB is updating there systems and taking so long. I am definitely going to seek legal action against FNB for making her suffer like this without electricity or able to use her card to buy food.