Flight from SEA to NRT was downgraded from a new config 777 to old config. Recieved some email from UA appologizing for the downgrade and offering me a one of three choices. 15000 miles, a $350.00 e-certificate or 20%off airfare. The one I would have selected would have been the $350.00 e certificate however the certificate only applies if you have a US credit card and US billing address. I purchase all my UA airfares from Canada in CAD. The other rules for the $350.00 is travel within the USA which would be no problem Not sure if a debit card would have worked and did not want to take that chance. I do have a US debit card with Chase and US billing address but don't know if that would have worked since it stated credit card. Has anyone ever used a debt card to pay for a e-certificate?