I'll tell you a way: either directly search his company information and visit at home, or go to the sales department to make friends with the salesman, give him a little affection, and then borrow a word, because the salesman usually doesn't call you in front of other colleagues. Of course, the salesman doesn't really know the phone number of the planner. You can find the case manager in a similar way. I did this, I hope it will be useful to you.