unkown purchase

I have been a client for more than 10years and have never experienced any problems with the bank but recently infact yesterday i went into the app to make some transaction and i got the shock of my life it shows that there was an airtime purchase of R300 on the 11.01.2024 which i never did or logged into the app what puzzles me the most is that i never even received any SMS notifying me of the purchase and when i tried to find out what happened the banking app's Agent kept disconnecting my chats Agent name was Sbongumusa Cele I then spoke to Thobelani Zuma earlier today who was a great help i then send my alternative number the remaining balance on the account and again i got the shock of my life when i got to the ATM I couldn't withdraw because i entered an invalid amount which i do not understand at the current moment Thiobelani blocked my app and cancelled my Nedbank ID as well as removing my contact details ( ***)