can someone get away with saying they never got the product x ?
No, but they
can get away with returning the product while claiming it is defective, and they can obviously prove they returned it. They get their money back and you get your product back, so everyone's even. Except for your bitcoins, of course, which you'll never see again. Oops.
How about if the product isn't being shipped its a virtual product that has a proof they've gotten it all documented.
What proof?
Remember there is two types of fraud
a) identity fraud where someone OTHER than the cardholder uses the car without the cardholders permission
b) so called "friendly fraud" where the cardholder pretends that either scenario "a" occured or they never received the product.
Please explain how you can prove:
a) the person using the card is the cardholder
b) the product was deliver to the cardholder