FJ as a sportsbook has every right to cancel any match for any reason so long as they do it before it starts. You are not entitled to something because of it - had they done it when the game started or afterwards then you'd have a case here but as of now there is nothing. Bet was canceled BEFORE it was being played, what happened after matters not.
Excuse me but what you wrote does not make sense.
FJ can void a bet before it was being played
ONLY IF odds were obvious error.
OP placed a bet when odds were 2.60.
Bet was voided only after odds were down to 1.30.
When closing odds are 1.30 his probability of winning the bet were much higher than when he placed his bet. By voiding his bet, OP is the one who lost and not FJ.
This is not fair.
To summarize: - FJ can void this bet only if odds were obvious palp.
- If they wanted not to take any risk for this game, they should have forced him to fully cashed out his bet prior the game start but no way voiding his bet. Given
that odds moved in OP's favor, he would have a descent profit as well which is normal since he spotted good value at 2.60