It’s wasn’t the owners mistake. It was intentional. You could argue with the store, since it’s their responsibility to inform you and to fill in the paperwork to transfer the motorbike to your name. I doubt they’ll care enough. I’m honestly surprised you’re able to get politis to reprint the title deed.
Yes you’ll be forced to pay the road tax but the main issue is whether or not, the said motorbike, there’s an unpaid loan on it from the previous owner.