If you could not pick two seats side-by-side that probably meant that there were no such seats available anymore. Contacting someone will not magically make two side by side seats appear.
However you can only reserve seats in three cars of the train, which is often 9 cars long. So you end up in the crowded part anyway, as many tourists are unaware that:
- Reservations are not necessary on that train (and overpriced in my opinion).
- All cars have panoramic windows.
Just board the train and find yourself a couple of seats you like.