Faber — Copy of warranty card

My chimney is under warranty. I have the invoice to show the purchase date. However, the technician is asking a copy of warranty card, which i do not have any longer with me. If i have the invoice and the technician has seen the machine, why do you even need a copy of warranty card. My number and product details along with purchase date is in your system too. Please either send me a copy of this warranty card or ask your technicians to accept invoice.