While you were charging the battery, did you see the LED light blinking? If it was is blinking, that means it's charging. If it was blinking and it is still not turning on, there is the possibility of it simply being worn out. Please refer to the Troubleshooting page or the battery repair guide
The 7300 comes with four bits a grinding bit, a cleaning bit with two different heads( A Wire-brush head and a pressed cloth polishing wheel), a sanding drum bit( with extra sanding cylinders), and a mandrel bit. The collet is a 1/8th sized one. You can purchase additional accessories from either hardware stores or online retailers.
Don't worry - The blinking doesn't mean that there is an error. The green LED on the charger indicated that you properly plugged the battery pack into it. While it is charging, it will continue blinking. When charging is complete, the light will stay steady green.
Have you tried deleting some files from your phone? The reason why your phone is responding slowly might be because of how much memory is used up. Try deleting some unused files or back them up on a different device.