My Nexus 7 2013 having really bad problems now.

a) It won't charge even with the original USB cable & wall adapter. I have to turn off the tablet while the charger is connected, only then it will charge (shows the battery charging icon). I have tried other cables/adapter still no luck.
b) When connect to PC or Mac, the Nexus 7 is not recognized so I can't transfer files.
c) Charging real slow and then battery is discharging faster than normal. On standby can last only 2 days, before this standy can go for 3-4 days.

Running Android 4.4.2

Anyone else having the same problem? Not sure if this is a hardware issue or software/firmware problem.

How much to replace the USb charging port.on the 2013 Nexus 7?