First, and this is now water under the bridge, your iPhone was less than 1 year old and your best bet is always working with Apple in those circumstances and doing warranty service with them.
Now with the used phone. You had a broken used phone that is 10 months old and it is standard practice everywhere to replace your used phone with a working used phone. Apple will do this, Verizon will do this, AT&T will do this, T-mobile will do this and Sprint will do this. After 14 days, the phone is considered used. No one replaces with a brand new phone.