CRON TASK on php site sending email notifications

Hello Guys I need a php script running with a CRON TASK for sending email notifications together with customized messages to clients. The issue i try to solve... - somebody pays for a service on my client's website but sometimes documents are missing (this is an inssurance company) --------------------------------------------------------------------------------------------------------------------- The solution : i suggested to my client was to automate the email notifications to free his staff... --------------------------------------------------------------------------------------------------------------------- YOUR JOB : depending on the date of subscription recorded in my database, you will have to Build a script that will check EVERYDAY, which clients did not send all the documents needed - D-day + 8 after subscription : Send an email notification to the clients (each one will receive an email telling the missing documents) - D-day + 18 after subscription : 2nd notification to be sent by email - Including Customized message - D-day + 25 after subscription : 3rd notification to be sent by email - Including Customized message - D-day + 30 after subscription : Last notification sent by email to the CLIENT and TO the WEBSITE OWNER (so that he can send a post mail) - Including Customized message + I need a page to list all those clients and a tool so that we can sort them out. Clients who have received the D day + 30 notification will have to be highlighted