Hello Brz
Welcome to the SBB Community.
You have to hurry up and contact SBB directly. We are not the Customer Service and cannot help. Please call SBB now: 0848 44 88 66 (CHF 0.08/Min, waiting times are possible).
Perhaps, SBB is willing to revert the purchase. Usually, the GA cannot be cancelled within a minimum contract term of 6 months.
A travel card between Thurgau and Zurich is not a GA, it is more likely an Z-PASS ZVV-Ostwind Travel Pass.
Kind regards,
Roland