FNB ATM stole my deposit money

I went to an FNB atm in Randridge Mall yesterday and deposited money into the machine which was to go into one of my accounts. After the machine made the sound it usually makes when it counts cash, the machine swallowed the cash, gave me back my card and I got a slip saying 'transaction unsuccessful'. The security guard there said that I must come in on Monday because the branch is closed on Sundays and he said that I “might” get my money back. I put my card back into the machine to check if anything might’ve reflected in my account and all the options I had to withdraw cash were all blocked and my app kept freezing when I tried logging in. Please sort this out FNB, you can’t be doing this ESPECIALLY to students who have to live on a budget.