I have same issue re my Switzerland tickets (swapped my hungary ones, well the seat with at least!)
After a complete nighmare experienced on the booking site and an expensive first game choice!, I thought I would start a thread for future ticket swap. many of us have single tickets for a different category form our friends/family
e. g.
I have a fans ticket for Swiss game and my son has cat3. if someone has the same issue we can agree to add the 'seat with' codes now for each other and swap the tickets later.
I'm happy to take either category in the swap to sit together.
if interested message me
Cheers