What can i do if customer wil start shouting to me?

just keep quite and watch him or her shout till the time he or she calms down then u explain things to him or her in a polite way

first ask quietly to calm down , telling that your job is to help him as a customer service rep , keep a low tune of voice , if customer is too angry get his attention by raising your voice saying we are sorry for inconvenience , let him explain and talk so you understand issue , then recap it and brief him out on how to solve it , by explaining steps your doing to fix it. always drop an email or a phone number for any feedback he needs to send at any time :)