I want to take my users ip addresses and make an if statement that bans 1 ip from having 2 accounts.

I'm new to WordPress and web development, trying to make a classifieds website where i need to verify that each person has only one account. Sms verification is very expensive and email verification is useless. I want to log all users IPs and make an if statement that says if an ip already is tied to an account, then I don't want them to be able to make another account.