Hello NikosNZ
You can reserve seats in the app, select « Purchase tickets » and scroll down, You will find « Seat reservation only ». Note that you can reserve only in the Intercity from Zürich to Lausanne or Brig, but not in the Interregio to Martigny.
No mail address is available. You must call the Contact Center:
0848 44 66 88 in Switzerland or +41 51 225 78 56 from a foreign country (24/7, waiting times may occur).


Kind Regards
Danhiel