The fastest way is to call them - they will give you the booking class immediately and you can also ask them on the phone to re-send you the e-tkt confirmation in which the booking class is clearly stated.
The phone number is: +48 22 577 77 55

On original ticket it's here:



On etkt confirmation sent by Warsaw call-centre it's here:




If you call them during busy time one of stations / local city offices will answer the phone, then on such confirmation it's here: