Looking for a rule - No defense on robots without tubes

i'm sorry for complaining, but the refs made this rule, and said that would be strictly enforcing all the rules of the game, but then it seemed like they didn't. In our final seeding match, we were hit, causing us to drop our tube. The opposing robot then backed off, and rammed us again, before we sould even lower our arm to the ground. We tried talking to the refs about it, but they said they didn't see it happen. If they saw it, we would have won because we lost by only a few points, and the opposing alliance would have received some kind of penalty.

About it being a rule, it doesn't matter if its in the book, cause the refs are going to penalize you if you don't follow it, so we followed it regardless.

Edit:This was just the most striking example. I'm pretty sure that they hit us one or two other times when we had no tube, and i beleive that they hit one of our allies, but i'm not as sure about that, because i was more worried about our robot at the time.