I am unable to add my credit cards to Apple Wallet

The terms and conditions are sent by the bank to your iPhone. If you’re not receiving them it’s your bank blocking the cards. Apple does not verify cards, your bank does that. Each bank will be trying to mitigate the fraud risk.

No offense, but three different phones with three different Apple IDs is a major red flag for most banks. You’ll need to resolve this with the fraud departments at each bank.

A work around is if the banks allow you to directly add the cards using the banks secure website or mobile app. Login to your account and see if you can add your cards that way. Most major banks permit that.

Yes, the issuing bank controls the number of devices a single card may be added to. Typically that number is 9 or 10 devices, but I’ve seen and lower limits.

Do you receive the terms and conditions and agree to them electronically?

What is the exact error message you’re receiving? Why are you adding your cards again, did you get a new iPhone? What bank issued the cards?

So, why did the cards get removed?