I bought the non steam version of Heavensward off of gamestop, not realizing that it wasn't compatible with the steam client version and I am looking to trade the non steam key for a steam version of Heavensward.

you should contact Square-enix FFXIV support maybe they can help you

Support pretty much told me to get a refund which gamestop doesnt do with cd keys. Still looking to trade key for steam version of heavensward or something with same value.