Here is some info I found only so that you understand better what maybe the issue, I think you will have to return your iphone, or before I do that I will go to an Apple Store so that some one checks my iphone, sometimes they could fix it very fast because they have special tools, or if you want a new one return it but you will have to wait a lot of time because the iphone 6 + is sold out.
Apple iPhone 5S Ear Speaker Troubleshooting:
The Apple iPhone 5S Ear Speaker is your main hearing piece when using your device in normal phone mode. The ear speaker is not the same as your external speakers for playing music. The ear speaker also does not control the sound when using your phone in speaker phone mode. If you place your phone to your ear to answer a call, and you have no sound, then this is the part you need.
Make sure your ear speaker is fully covered by the protective plate on your iPhone 5S. The ear speaker on this phone only fully functions once this shield is on. This shield aids to direct the sound outward to your ear instead of inward at the internal components of your device (they dont listen well anyway). If this piece is missing, or nor on correctly, you will need to open your device, and tack it down before your new ear speaker will work again.
Check the springs (the copper prongs) on your ear speaker. They are designed to maintain a constant connection on your device, and if one of these prongs is not long enough, you will need to stretch it back into place before your new speaker will work.
If your hear a buzzing noise while taking a call, your new speaker simply is not tight in its fitting. Open your device, make certain your ear speaker is aligned correct, and tighten all the screws that hold this part in place. Your speaker now should work normally.
If your ear speaker is tight, all the prongs are touching, and the cover plate intact, then you may have a defective or broken part.
