A4 2017 Allroad Sat Nav Unlocking

[picardy]

I have just taken delivery of my new Allroad and didn't pay for Sat Nav as it was £500

I see here that I can buy the card for £60

GENUINE AUDI A4 LATEST SHAPE B9 SAT NAV NAVIGATION SD CARD EUROPE 2016 8W0919866 | eBay

But they say it needs a code from Audi. Is there any other way of unlocking the sat nav and what might Audi charge me?

Thanks in advance for any comments.