Agree with the above ... used webcertificate several times with no problems. Technically, it's a MasterCard.
BTW, Mypoints offers Wal-Mart gift cards as redemption option. The Wal-Mart card is 1400 points for $10, while webcertificate is 1500 points for $10. webcertificate also has an option where 3500 points gets you $25. If you have only a couple thousand points, the wal-mart option is better.
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On the road, In the air,
I enjoy travel, From here to there.