If you will, think of yourself as a horse for a minute.  Your handler puts your halter on, leads you to the hitching post and ties you there. Another person walks up to you, bends over and grabs the tendon on your front foot. You pick your foot up to pull it away from him and before you can, he grabs it and starts gouging your foot with a sharp metal tool. If you are a horse that is fearful, distrustful or just untaught, this might be too much for you. Then when you pull your foot away from him he yells at you, hits you or worse.  All you want to do is get your foot back and be far away from this person. This person is using force and not building trust.

YOU MAY ASK WHAT CAN I DO TO GAIN HIS TRUST?
"BE KIND, FAIR, and CONSISTENT
"DON'T punish him for making a mistake.  Just give him something to do that he can do correctly and give you a "yes" answer
"Reward him often for giving you the correct response
"Become  higher in the social pecking order than he is

HOW CAN I COMMUNICATE WITH HIM?
Look at what you want the horse to do. Develop a lesson plan with lots of steps repeated lots of times to make it easy for the horse to understand what you want from him.  Put something in the plan for the horse as A REWARD for doing what you want.  This could be nothing more than a rub (NOT A PAT) on the neck with soft kind words of praise, often. Work only on ONE step at a time.