Problem With Gateway Mt6728 Battery Problem For Gateway MT6728?

Battery problem for Gateway MT6728? - problem with gateway mt6728

I have a Gateway MT6728 laptop, and recently I had problems with the battery. I plug and the battery are still not being used and is free. I asked my brother about this and said that the battery is empty and not a burden, in fact, I have to buy a new one. I am looking for a line, but I can not find to buy a battery. So, if you can help, here is some information about the battery:
Gateway 6MSBG
Model No: 3UR18650F-2-QC-MA1
Lithium ion --
Review 11.1V 4800mAh