Sorry for the trouble this caused @Mountain! 

At this time we can't guarantee that every virtual card will be accepted with Square. Additionally, card-issuing banks don't share the reason a card is declined with Square, so your customer may also contact their bank for more information. 

If this card is still being declined, I recommend asking your customer to pay with another card/form of payment.  

Or you can send your customer an invoice. That way they can enter their own card information from computer or mobile device.

Hope this information is helpful! Let me know if you have any more questions. Happy to help!