Paypal won let me use my Mastercard?
you say “I verified my account. But when I try to purchase again it says “enter 4 digit paypal verification code”.” then you did not verify your account. Look, it is quite simple, 4 digit paypal verification code is in your statements. That’s it, look in the statements. Get internet banking or wait for your statements. Failing this, give up and walk into a shop.