Locked out of my settings when I had to sign in again

I have an iPhone 7 it's updated and I have locked myself out of an important app and they can't help me login in or override it from my bank! I only got some weird messages from you about a threat on my phone and because I accidentally lost my access to my fingerprint unlock to the app but nothing else and nothing else has changed but I had to sign in with you guys a couple of times because I was out of service and it kicked me off again how do I fix this I have to access my bank