I have recently learned, by accident, that there are e-certs which are for single use only. I opted to accept a $600 e-cert from Customer Appreciation for an international flight cancellation. I used it for a MR valued at $150 and was told that the residual would be available for future travel. This is WRONG information, as was explained to me by IK MP Service Desk. It was a major issue to have the residual retrieved and given to me under a different e-cert type and number. I was told that I needed to make sure that, if offered an e-cert in the future, it was under the program "13TCVA" otherwise it would need to be redeemed on one single purchase. Can anyone tell me if the e-certs given for VDB are for multiple purchases or are they single use only? Thanks.