Warrenty - Question

Good evening Community,

I'm close to get a Z30, it's just the question where. Either T-Mobile (Germany) or Amazon (Germany).
Currently I'm having an iPhone, and it was once broken, the wake/sleep butten didn't work anymore. I went into the Apple store and got a new device.

If I now buy a Z30 from Amazon, and for example the wake/sleep button on the top is broken and doesn't work anymore, will Amazon replace the phone too? Or is it being fixed over Amazon? How does it work with Amazon?

Also another Question:

If I got the Z30 from Amazon, and i put in a T-Mobile SIM card, will I still get the updates from T-Mobile?

Thank you in advance!