I'm trying to use a $250 e-certificate from United, but am finding almost no eligible flights, even when I seem to be following all the terms and conditions. Has anyone had this experience before? The flight I want to use it for is operated by United and is not G-class, as specified in the rules, but it still won't apply the amount of the certificate to the price. I'm pasting the T&C below, in case it helps. I enter the certificate number when I search for flights, and am finding MAYBE one flight a day that it can be used for, if that. It WILL let me use it on a first class fare for the flight I want, but not economy. Any suggestions would be appreciated.