Don't worry. It isn't necessary for you to send the hard copy of your invoice along with your product. Just remember to upload your copy of it when you are filling the warranty claim form. It is imperative that we get a copy of your invoice so that we can confirm that your product is still in warranty.
Also, don't forget to mention your Warranty Case ID (WCID) number on your parcel so that it is easier for us to identify it and avoid any delay.