Can't charge battery after upgrading to iOS7

Battery was perfect (at least apparently) until I installed iOS7. After that, at first when I connected the phone to either my mac pro or macbook, none seemed to acknowledge the phone was there, and the guy wouldn't charge. Then I connected it to a pc and the battery indicator on the screen appeared. Yay...no, because although the pc detected the phone, battery charge was going down, down... until it died.

Today at the apple store they installed a new battery. It was half charged when I got home but again the same thing, not charging. So I downgraded the phone to iOS6 but still the same problem, not charging. So it's not the battery, it's not the iOS! Now what? Anyone encountered something like this?

 

They did a lousy job, for sure, I paid for a battery that was not the (only?) problem and they didn't investigate further.

Although it was beta ios7, they said they could do something as long as it was hardware related, which seemed to be the problem. And now back with ios6, as the problem persists, it seems it's actually just hardware.

Time to go back to the store.