When you buy a product "blindly" without looking into the T&C, then you only have yourself to blame.
I believe the service centre you went to in Orchard would have placed a notice somewhere to indicate that they do not service iPhones... and apparently you didn't ask either... :dunno:
If you had checked the Apple Singapore website,
http://www.apple.com/asia/buy/locator/svcindex.html you would have realised that only Singtel is authorised to do replacements, as the other Apple service centres only do "Hardware Services offer: Default Apple products except iPhone." For the "normal" service centres, they don't really "repair" Apple accessories or iPods... they do replacement if covered by warranty. Out of warranty means you're outta luck.
If the service centre or even Singtel were to tell you that they could fix it, but it would cost more than $350, would you be willing to pay? Sometimes the cost of labour or even parts amounts to a lump sum.
And I'm pretty sure that no one asks when "Where can i get my <insert brand> hp fixed if i break/drop it?" when they buy that specific brand of products. Yes? No?
That said, I'm still a satisfied iPhone user myself.