The groups department is not closed. I, literally, just spoke to them. They have remained open throughout this entire time in order to deal with existing and new, future bookings.
OP, try calling 1-407-939-4686. I don't know if they will speak with you as you are not the TA, but perhaps they can give you some insight as to how to proceed. It is possible the tickets were not purchased through groups, but none of the WDW ticket offices are closed. If you get through to groups, you can ask about your tickets. If they don't offer you any information, try calling 407-566-4985 which is the "existing tickets" dept.
I'm sorry the TA is not helping you through this situation. There are tons of TA's out there that are dealing with both WDTC and group reservations and, except for the initial cancellations when hold times were exceptionally long, it really hasn't been difficult, at this point, to get through to the right departments at WDW and handle these issues. I'm not sure why you are getting such a runaround.