From user to user:
Mobile app accounts can easily log in on PC - same user, same PW.
FB accounts have been transported/transformed. Try the same as above. Consult WGT's help pages. "Contact" WGT (below).
Explain to WGT why you have two accounts and which one you want to keep. Accept that one will be inactivated - better than to get both purged (which may happen, perhaps).