Question

what decision will be given by referee if team refuses to play after instruction is given by referee

Answer 1

The referee can give a red card to the team if the team refuses to play even after the instruction is given to them by the referee.

The red card indicates that player or the team has committed the serious offences in the game.

There can be serious consequences if the red card is given.  

Answer 2

Which sport are you referring to here.

In most sports,if this happens,the team that refuses to play is considered to forfeit(quit) the match.The opponent will be declared winners.
Hope this helps