charge or no call?

[oc]

A-1 ( a small guard) drives the lane and crashes into B-1 a big post player who had legal guarding position. B-1 jumps up straight to block the shot, A-1 initiates contact into B-1's chest but because of the size difference B-1 blocks the shot and maintains his position coming down to the floor on his feet, A-1 however falls backwards.

I am sure many of you will say you would have to see the play, but without seeing an just going on what is written-what do you have--charge or no call?

(--I called charge--more experience partner thought it should be a no call.)