I just got certified a couple of weeks ago, and just center reffed my first couple of games. In the U16, the coach was disrespecting the linesman. At halftime, the linesman told me about this and I told him I would talk to the coach. When I did, the coach started cussing at me. I decided enough was enough and I gave him a red card. Afterwards, the head ref of the league told me this was a wrong move and we weren't supposed to card coaches. My question is, if I can't card a coach, what do I do the next time that happens?