I downloaded the steam app. It appears that there is no way to play a WGT game as a member of WGT. I have been a member of WGT since 2009. I have to assume that our WGT accounts will move over to steam when WGT is ready. If that is not correct please advise.
If you are using facebook to log on. It won't work.
Put in your user name and then click forgot password and see if it gives you a reset. Thats if you have an EMail through WGT.
Otherwise send an Email to Members@worldgolftour and explain your problem.