For any issues with the offer please speak to O2 customer services via 4445 if you're a Pay & Go customer and 202 if you're Pay Monthly customer. If you're having trouble downloading the voucher, please generate the code in an area with network coverage before going in-store to redeem. Do not click “use now” on the app before you reach the relevant participating location. When at the location (and not before) you must click “use now” on the app which will generate a code on your phone with a limited time period to use the code. You must then present this code to a member of staff at the location in order to redeem the offer. One mobile voucher per person. Screen shots will not be accepted. This promotional code entitles you to receive one free Carabao energy drink (330ml). Three flavours available are: Original, Sugar Free, and Green Apple. Subject to availability. Available only in WHSmith Travel stores. Excludes Highstreet, Outlet stores, Online and ‘Books by WHSmith’ at Selfridges, Harrods, Arnotts and Fenwick’s, WHSmith ‘Local’ and motorway service station Travel stores. Cannot be used in conjunction with any other voucher offer. Online and Internet-enabled phones required. This offer is valid for one code per customer and cannot be used in conjunction with any other voucher offer.