Helping Complete PHP Quiz

Hi,

We are developing a learning system using PHP, from time to time we face issues which I can’t fix. We need senior PHP developer to help us fix things.
The current issue we are facing is we can’t complete the quiz section, which is almost done 70%.
Task already done.
• Create questions pool
• Assign the quiz to a course
• Students can take the quiz
• Quiz questions are randomized
Tasks need help (Scope)
1. Quiz timer
2. Create back button so the student can review the previous questions
3. The student after finishing the quiz can review the quiz answers (if this option was enabled by the instructor)
4. Limit the students quiz retake to specific number and specify time interval between quiz retakes.
5. Quiz result to be send via email to the instructor and the students.
6. The instructor can view the quiz question take by the student
7. Randomize the quiz answer options.
8. To be able to import and export quiz from CSV.
9. To issue PDF certificate when the students completes the course and passes the final quiz
Note: Developer will be given remote access to fix the issues on our developer localhost machine to demonstrate the working code.
Due date: five days from the milestone creation.

Please read the scope and then bid.

Best regards