Thank you for your request.
I've already replied to you on Instagram. I give you the same answer.
On the Interlaken Spiez route, is not necessary to make a reservation.
For trains Spiez - Milano, Milano - Bologna and Bologna - Venezia = The number of your seat is on the ticket, right of the “01 SEAT” (for example 85 or 3D).
For data protection reasons, we do not have information about our customers' orders via Community. I advise you to contact our hotline directly at +41 848 44 66 88 (CHF 0.08/min.) or if it does not work at +41 51 225 78 00, my colleagues will inform you.
Note: I have hidden your order number for data protection reasons.