Which day are you flying ? - there is also a flight BRU SXB - SN3655 at 0940 am
* Strasbourg is indeed less than 1500 km - around 450 km
* I would definitively ask the SN Customer Service desk to get compensation since they cancel the flight - their number + 32 2 723 2323. There is also a ticketing desk at the airport with SN managers.
* If it was a paid ticket, I would ask them to fly me to Basel (140 km from SXB) and pay for transportation to Strasbourg so I can be there on time. As it is an award ticket, I think they will not put you on the flight to Basel since it is operated by Swiss.