I need the basics

Hello. I am a mac graphic designer and need to update a web page for a site that has a feedback form. The hosting service does not support cgi scripted forms anymore so I need to insert php scripting. I have no idea what to do. I had assumed the hosting service would provide this to me so I could paste it into the html page. They said I need to provide the script to them for review and then they will place it in their server. After reading a bit on php, I really am not sure what I need to do. Can you help me with a basic understanding of what I need to do? I feel like their webmaster should be able to help me with this as part of their service. Does this sound reasonable - or should I switch ISP's? Your help is much appreciated, TJ White