Unfortunately, sometimes when people want to shut down and shut another person out, for whatever reason, there isn't anything we can do or say that is going to make them change their mind about it. And calling and messaging, I feel, only serves to push them further away. Even though it's hard, and it hurts, it sounds like he needs space. Let him come back to you. He obviously knows how you feel. It may be a good idea to make plans to stay elsewhere when you are on business this time, even if you do end up talking again.