whats the rule if the other team refuses to play because they think the referee is bias?...we call it here in the philippines a (WALK OUT)

should be the score at the time of the stoppage shall stand?
or should we give the winning team a +20 points?

The rule is it's a forfeit and they can piss and moan all they want with another notch in the loss column.

As for the score...

My understanding is that if the team that is behind walks out, the current score stands. If the team that is ahead walks out, the score becomes 2 to 0 in favor of the team that didn't walk out.

I belive that is NFHS rules, if you play FIBA or NCAA or other rules, you'll need to check with those rules.

You are correct, sir. NF 5-4-1. In order to have the forfeit, however, the team that forfeits must have been instructed to play by an official. Technically, I guess this doesn't cover a team that doesn't even show up.