Rahul,
As Cornelius said, you can reach out to PMI with all required information.
You can also try finding the exam fee receipt under Certifications - Order History.
After logging in, I clicked on certifications and then PMP. It said that I am already PMP certified and on the left tab, there is an order history option where you can see the exam fees you have paid. You also have an option to download the receipt. Hope this helps.
Thanks
Nagarajan N