Cheap Flights from Toronto (YYZ) to Zurich (ZRH) from CA $562

The only thing is that we spent 346 dollars for extra leg room and there were vacant seats for extra leg room and people took the seats without paying the extra ... some people were asking to sit on the seat with leg room next to us and we refused as we paid so much money for the comfort .. wondering if we can get extra leg Room seats on our flight back to Canada on May 5 free of charge? Feeling that it was not fair for us to pay extra money for the seats while others are taking advantage of empty seats with leg room and not paying ! Please reply to me .. thank you