Hi, I'm Humayun Ahmed.
"Custom field in checkout page is not reflected in the mail" What do you mean by mail?
Your statement is not much clear. But, I think you have some UI issues or Design tweaks.
Am I Right? If yes, then no problem I can fix it. Because, I'm a front-end developer.
I have recently started freelancing. Hope this could be my first task(If you give me the chance).
Waiting for your positive reply.
Regards,
Humayun