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Accepting any credit card where the customer swipes the card or the card number is typed in manually shifts all liability to the store from the credit card company. We do not recommend ever accepting a payment entered in either method. If the customer decides to do a charge back, you will not be able to challenge/win that charge back.
Do not take charge the same credit card the same amount on the same invoice on the same day. Some banks will see this as a duplicate charge, and you may not get paid for both charges.
If you take a voice authorization, always call the number on the back of the card. A common social engineering way that stores get defrauded is when a card gets declined. The customer then says it’s just an issue with my card, this terminal, or something similar but it’s okay, I have the credit card company on the phone. They will give you an authorization number approving the charge but it is actually a co-conspirator on the phone, not the actual credit card company. Calling the number on the card yourself should help prevent this fraud method.