Mobile app abroad

I am currently abroad until December 2024 and am unable to log into my mobile banking app as the OTP is being sent to my South African number which I no longer have. I have requested that my OTP rather be sent to my email and I accept the risks there of.

FNB keeps on stating that I are trying to contact me on my USA number, but I am not receiving any calls. It is almost month end, I need to log into my app to make payments etc.

How to resolve the issue?