Unauthorized online transaction

SCAAAAAMMMMMM!!!!!! On May 31, 2025, there was an online transaction that went through without my authorization, which surprised me. Normally, when you purchase something online, the bank will send you a pop-up message to connect to your banking app for payment permission, but I did not receive it...I tried to go to the bank at the Mall of Africa. I was told they wouldn't be able to assist...I filed a case on the app, but no one called.I tried to phone the call center number and was told that the ***** department will contact me till today. I'm still waiting for a call.