go have sex with them!
Think about them logically and find out by all the information you got,what is the best way to solve it.
Do it calmly and very firmly. In other words dont yell, make sure everything or everybody is alright if not help from your manager is a good way of finding the solution
Always document events and communications in writing!!
Think that u r one of the boss for the company or for ur job......
show them attitude