Situation with 5 seconds left

[Ref_ Fred]

I was calling a spring HS boys game. 5 seconds left team A score a 3 pointer to be within 1 point. as the basket was going through the hoop. the team A called time out. I was in the trail at the time the basket was scored. the official under the basket didn't grant the Time out to the player 5 feet away from him. with some delay I see the time out being called and grant the timeout. The coach from team B, had a valid complaint that team B already had possession of the ball underneath thebasket and the time out should not be granted. The end result was I granted team A the time out. They stole the ball on the inbounds and score with 1 second left and win by1.

Please give me any opinion and or suggestion to this issue.