Disappeared money

Switched Banks, Capitec to FNB. I transferred R600 to my new FNB account on Friday evening that cleared Sunday evening and reflected on my account. Now I'm trying to buy something the card declines which was a shock because there is money in the account. To my surprise when I check on the app, the whole amount is gone and nothing is showing under account history with regards to the money that is now gone. How can money just disappear Just like that? Can someone possibly explain what could be the reason for this. Wow, what a way to be welcomed to FNB!!! 😏 I am actually regretting my decision! I was about to submit my form to hr to start receiving my salary on FNB. Glad you've shown your colours before that! But for now, please explain where my money has disappeared to!