Not sure you will get a refund. I constantly get reseated. Usually my family stays together (when on one single PNR). Where things go south is if we are on different PNRs.
I never managed to get a refund though - they put themselves on the point that a set is a seat - within any of the three "zones" (preferred, leg-room, rest of of the plane). What particularly annoys me is that in this logic the consider a middle seat "equal" to aisle or window seats... which no one will agree to...
This is one of the things where the Easyjet and the like are really ahead of Swiss - I never had any of this Mickey Mouse with them. There you pay for a seat - you sit there.