When you go into My Account > Passes & Vouchers and Bills & Payments whilst logged in on here is there any indication of the mobile sports pass ?
If not is there any chance you bought the mobile pass on a different account ?
Did you get any email order confirmation from NowTV that you have purchased a mobile pass ?
Should the pass be showing on your account on here, then make sure you are logged into your smartphone only (tablet not permitted) and try and watch one of the five channels that allows you to watch with a mobile pass.
Sky Sports Channels that you can watch with the mobile pass are Premier League, Action, Arena, Racing & News (All other Sky Sports channels will not play with a mobile pass and you will be prompted with a message to buy a pass).
See if live chat can figure out where your sports pass is on your account.
To reach live chat, open the link below, select the most appropriate category, then pick the nearest help topic, then scroll towards the bottom of the screen page and click on the green arrow underneath Get in Touch to show the live chat button.