I need money to be reversed

Yesterday around 4:30pm I withdrew 250r on my card and came through on my phone but I didn't receive it on the atm.. The atm started jamming. I called fnb they told me there's nothing they can do I need to go to the branch.. My worry is what if at the branch I don't get help because I ddnt even get the slip.. Please help me I can't loose such an amount of money while I'm unemployed