traveling or pushing??

[81artmonk]

Sorry guys I have a lot of questions.

Player A gains possession of a shot ball on the rebound. Player B is trying to do the same, and in the proccess runs into Player A and causes her to fall down. Again I was taught that this is a foul. although in the game, the Ref called it traveling. He defended himself by using the old addage, it's a grey area and open for interpretation. Reading from other posts, I argue that contact caused the other player to fall therefore there isn't any grey area, it would be either charging or pushing. Am I right??