Sorry I haven't been back by, I got tied up, didn't forget about you.
If you have a subject focused, you have a range before and after that where things are in focus anyway. We call this curious optical effect "depth of field."
Beyond the outer range, there's a spot that we call the hyperfocal point. From that point to the depth of field limit, everything will exhibit a fair focus, but the optimal focus will be where you focused plus or minus a bit.
Using the app Photo Tools, I was able to approximate values for our phone using the optical geometry of the newer HTC One. The cameras are very similar in their geometries, and the app only allowed me to customize to the other phone - but optical physics don't change so this should be close enough for us.
Please note my screen shot by tapping the thumbnail.
It's complicated, so I'll break it down, I mainly posted it for proof and for your ammunition later.
I imagined that you were taking a picture of your sister 5' away. The calculations tell us that everything in view from 3' to 7' away should be in focus and looking sharp.
Let's not bother with a data clear, you can get that from inside your camera app by hitting reset under settings.
Please do go to camera, settings (the gear), image adjustments. I've got a modified version of the camera, so I have to ask - do you see a sharpness adjustment and is it at 0? If it's been slid into the negative, things will appear blurry. It's a special effect.
If you have enough light (sounds like it from your earlier post), no turning down of the sharpness, and even with subject movement, they remained within the optimal depth of field, and they're still fuzzy, then I'd take it back. At the very least, compare to the floor model.
You can go to your app drawer, Sprint Zone, help, call customer care. Tell them that you want them to schedule you an appointment at your nearest corporate store, you have reason to believe that your phone camera is defective. They'll set an appointment so you don't have to wait around. You'll be logged as having a problem, so you won't have to argue with anyone in the store, and they'll follow up to make sure you were taken care of.
If you get an argument about focusing, tell them physics dictates what your camera can do and pull up the ammunition on your phone browser. Long press the thumbnail to open it in another window.
Again, sorry to be late and wish that I had more helpful advice. But this is may be for the best. Let's be sure that we're not fighting broken hardware.
By the way, I presume that your lens is clean. Plastic eyeglass cleaner is ok here. Not too much. It's not the perfect way, but I'll brush or blow out debris first from the lens (lens brush, clean unused makeup brush is ok), then dampen (not soak) a qtip with it, then point the qtip straight into the lens and GENTLY and slowly give the qtip a good spin. The cleaner is doing the work, it's not a windshield, don't use pressure. If you get cleaner spots left, get another qtip, try again.
Anyway, hope this can help.