Bad after sales service

I bought a Ford Everest 2.2 XLT Auto new in 2017 .Since the day I bought it Ford are not able to update the navigation system and the only reply I have been getting for the past year they are working on it.This was one of the selling points of the vehicle and if they cant keep it up to date it is of no use to the customer as new roads are been built all the time and changes made.The other navigation systems like Garmin and Tom tom have constant updates.My vehicle has just over 10 000km on and if they cant resolve the problem they must fit a new navigation system to my vehicle.How can you sell a product and not give the back up????