Looking out for HR recruiters on performance basis

I am looking out for HR recruiters or agencies to partner up or provide me recruitment end to end services. I will give you requirements and one need to fill it with below conditions 1. 8% on fixed annual ctc will be paid to you. 2. if candidate doesn't join as promised, you provide for 2 backups always before hand. 3. If candidate leaves with in 6months, you are refunding the fees charged. You can make replacement too, and bill for it separately to keep accounts clean.