Trying to get a new phone and out of the blue is declining my credit card that I pay my monthly bill with. When verify my address and then ask me for my payment method. I pick credit card debit card fill out the information which they should already have on file and it tells me that they're saving a new form of payment. to my account. Which is not a new form of payment it's the same payment I've been using for over year. Then I get declined
You also may want to check with the institution that the credit/debit card is through, could some sort of fraud protection be enabled that it denies charges above a certain dollar amount for certain categories (electronic devices) from not 'approved' sites?
That is if you are certain you are entering the information correctly.