FNB App Deactivate

Can you please help me to deactivate my FNB App from the following cell phone model Samsung A32 it's went for repair now I am struggling to approved my online banking because the phone that I am currently using doesn't all me to download FNB App. I have try calling FNB Online since Saturday afternoon no one is willing to help me I have already finished more that R100 airtime I just finished calling FNB online now I was told that Nkosinathi is the only person who can assit me because he open a profile for me but someone from the call centre told me that there's lots of Nkosinathi. Can you please help