Help How to exchange m8?

[L4asong]

How do I go about exchanging an m8 that I bought online from AT&T? Do I go into a store or mail it back to them?

Reasons:
Top speaker grill not flush with screen
Volume button loose on both X & Y axes, makes a rattling noise when vibrating
Power button loose on X axis

 

[SolApathy]

I would contact AT&T customer service on the phone. They are the ones to speak with to answer their questions.