If you want to find a good new battery, follow this amazing thread that @Greywolf74 made. It shows the performance of many different brands of batteries at different price points.
Well you need to make sure the battery is at the lowest voltage possible before disposing of it. You can make a setup using an incandescent 12 volt light bulb and leads to the battery. This will discharge it to the lowest voltage possible. Make sure to watch the battery and keep it in a...
It looks slightly puffed, it’s not safe to use anymore, you need to discharge it and dispose of it. What charger do you currently own if you do own one? You need a charger that can discharge the lipo to 0v.
It might be possible to fix the esc wire by cutting and soldering on a new wire but that isn’t guaranteed to work. At that point I don’t think it’s worth it, it’s also a Chinese brand so part availability is scarce.