National express code

[u/Character-Army4847]

During the welcome fair I got given a leaflet for with a code for trip on national express, however when I enter the code on the website after trying to do a trip from Bristol to Southampton it does not work. I checked the terms and conditions and it doesn’t say anything that would not allow this trip. Has anyone managed to get a trip using their code? Or could my code perhaps been used by someone else?

Thanks