We have to examine the warranty policy and procedure, in case if in the warranty procedure it is mentioned that you have to produce original invoice in such a case you will have to produce the original invoice. 

As an alternate measure, in case the warranty policy requires you to produce the original invoice, and if the invoice is computer generated by the retailer, you may approach the retailer and request for another copy of your purchase citing details like date, name, etc.

Kindly contact us for any further details and action.