Consumer rights in Turkey - a lovely theory. My experience is that if you buy from the good guys - Eren Spot, Vestel, Beko, even Migros, if anything goes wrong within the guarantee period they put it right - most exceptionally in the case of Eren.
Buy from a small retailer, it is "Buyer beware". Not always but often.
I bought 2 bikes for the girls, not long after we moved here. Small shop on the "back road". Not exactly expensive but you do expect a certain level of quality (ok I don't anymore). "All one year guarantee" the owner told me. Imagine my disappointment when within a couple of months both bikes started to fall apart, same problems in both. I took them back to the shop and explained. The owner was amused. "Not this bike! THIS bike!" he said. "If you buy this bike, one year guarantee. You buy this bike, no guarantee".
So there we have it. What do you do? Let's go to court, spend the next five years hemorrhaging cash in the pursuit of a small amount. Principle is principle but I for one couldn't be a**sed. And they know it. I'd probably lose anyway.
Two bikes, taken to a motorbike repair shop made almost entirely from scrap wood, and sorted for some ridiculous fee, 9 lira or the like.
My advice is to stick to the more established guys. I would go as far as to say that if Eren Spot sold everything, I would buy everything from them.
You can always buy cheaper here. 5 hours of tough negotiating and you'll get it 50 kurus cheaper in the end. But it isn't all about what you pay.