Help with a High School rule

[goodsir]

I am not a High School Football Official. I hope the terminology I used is correct.

Under High School rules.

4th and 5 at B's 5 yard line. A1 throws a legal forward pass to A2. A2 jumps straight up and possesses a pass about a yard inside of the end zone(both the ball and A2 have broken the goal line plane). B3 makes legal contact with A2 forcing him back to the one yard line and the catch is made at the one yard line where A2 is downed. Had no contact been made with A2 he would have made the catch with the ball over the goal line. The contact by B3 made A2 come out of the end zone and when his feet came down for a catch the ball was not across the goal line and A2 is downed from that contact at the 1 yard line.

What is the ruling?

Same scenario, however A2 when knocked back stays on his feet runs back to B's 2 yard line and is downed by B4.

Thanks for any help.