Payment gateway integration in PHP script

Hello, I am looking for a PHP expert having experience in payment gateway integration. https://codecanyon.net/item/gigtodo-freelance-marketplace-script/23855397 this is the script in which an Indian payment gateway needs to be integrated. Razorpay, Paytm or Cashfree are some alternatives.
If someone has already worked on this script that will be a plus point.
Please quote your time and budget to get it done.
Thanks