need expert in php for mail settings

I switched to new host. all script files, and database is complete and site is almost functional with exception of sending mail from the site. This is phpfox clone and on old host the eentire script works flawlessly. need to get mail to working flawlessly here as well on new host. things that need addressed: all mail for site. I want all mail functions to work as they are supossed to. You must be very experienced in php and the functions of mail in php. NO BEGINNERS apply please. must know exactly what your doing and how to trouble shoot problems. I know the script works flawlessy as it has been in use on different host for almost a year. Please dont tell me it's my hosts' problem or server problem as i know it's not. I have worked these issues out with the host and it's all setting withing the script.. must be willing to communicate constantly to ensure no time is being waisted. this project is to get all script mail to function flawlessy. this same thing had to be done when script was placed on old host so i know with the right programmer this will work for new host as well. Please dont waist both our time. Know what you are doing.. must be able to start now .. thanks and good luck