Payment gateway and multiple entries sorting

I am looking for somebody experienced with payment gateway integration and multiple entries sorting. The payment gateway that I need integrated is like PayPal (basically banking). Additionally, I need to sort through user data entries with an expected volume of 1,000 to 10,000. In order to be successful in this project, you must have experience with PayPal gateway integration and sorting through user data. A successful completion of this project will require you to deliver a fully functioning system with updated user data. If you are confident that you can provide this service in a quick and accurate manner, I would be very interested in working with you on this project. Thank you for your consideration.