If you're level 53, then Heavensward is definitely registered to your account as you would not be able to earn any exp past level 50 with just the basic game, so it's not likely to be a licensing issue.

I suspect this is an in-game bug which you should report in the proper channel:
http://forum.square-enix.com/ffxiv/forums/632

Please be sure to follow the template here, or they won't even read it:
http://forum.square-enix.com/ffxiv/t...-THIS-FIRST%29