Pushing Bots

Just double checking, but are you able to push an opponents robot? At a recent competition that my team attended, one of our opponents pushed us for a good 5-8 seconds and the refs didn’t call it. Correct me if I’m wrong, but I have read in the rule book that it is illegal.

Pinning your opponent against a field element for more than 5 seconds is not legal. Pushing has been ruled to be legal.