Laptop battery not charging, battery not identified, 0% battery life

Hey, I really need help. I'm having problems with my laptop. It's a dell inspiron 7559 and was bought around January. Recently I have seen that the battery has no longer been as hot as it used to be when I first started using it. Along with the sleeve on the tip of the screen power adapter (below the part where the adapter lights up) has started to come off, exposing the wires. The battery has continually dropped down its percentage rate ever since I bought it, and it won't go back up. It is currently at 0% battery life and it says when you highlight over the battery icon ( plugged in, not charging). It also happens to show the BIO setup when I start the computer and shows that the batteries wattage and type cannot be determined. In the BIOS setup, the ac adapter type is unknown. The battery has not been through any harsh conditions along with the laptop. I have tried removing the battery, starting up the computer with the ac adapter (which is 130 watts), then adding the battery back, and ac adapter, then turning it on, but it had no effects. If I remove my ac adapter while my computer is on ,it instantly turns off. If someone can support me with this issue, it would be gladly appreciated. Thanks.