verification required loop

when i try to download a free app or try to make any purchases , im stuck in a loop of my phone asking for verification for billing info.after i do the verification the same message comes up again

first, i thought it was because the vanilla gift card i used did not have any money in them. so i removed all of them and it still did not work.

then i thought what if i bought a new gift card? but the phone refuses to add it, it tells me "Cannot Verify Payment information. contact apple support for more information"

it has been like this for about a week.

I do not want to reset my iphone and lose everything, please help me.

can i have any explanation on how to fix this