help

With so few details there is no way to know what really happened. I
get the feeling that the gas station put a hold on his account which
caused his over drafts. I would comment further but there aren't
enough details.

Sorry, it is your responsibility to know how much money you have in
the bank at all times and not to exceed that amount. The bank has no
responsibility to refund you the overdraft fees. I have seen too many
people get in trouble with overdraft fees because they use their debit
card for every little purchase, no matter how small. I saw someone at
the local 7-11 use a debit card to buy a bottle of water.