Build a private message on payment in my website

My website is live. It has log-in and signup working fine. Database is MySQL. Front end is PHP. There are 2 types of users who login, Customers and Experts, they are stored in different tables. Experts have a dedicated page. Log-in and signup are already implemented. What I need: ------------------ 1. A logged in User can initiate chat (like a Private message) to an Online expert. 2. User's chat should start upon clicking a Chat Now Button appearing next to an expert. (This is the challenge) 3. After user clicks on that button, first his login should be checked and if now he should be asked to login/signup. 4. After this user should be asked to give payment details and verify his payment. 5. Then the chat/PM starts between the two. 6. Upon session expire/ chat close, the calculated amount gets deducted from user's card or paypal etc. 7. This amount should get split up and deposited into website owner as well as that experts paypal account. 8. All data regarding each transaction and session should be written to a DB table. Terms: --------- 100% milestone and payment will be released only when full functionality is working as expected. Code should be standard and have all security. Do not bid randomly. Low bid amounts + good portfolio will be given priority. DO NOT BID VERY HIGH AMOUNTS.