I tried to buy a replacement battery, but that expanded dangerously until I noticed marks coming from behind the screen, so I popped open the case to have a loo

I tried to buy a replacement battery, but that expanded dangerously until I noticed marks coming from behind the screen, so I popped open the case to have a look and promptly removed it. I use a Third Rail case, so I can recharge easily. I don't use 3G, and all my apps work offline. https://www.amazon.com/Third-Rail-Protective-Compatible-Rechargeable/dp/B0050SHBOU https://www.amazon.com/Third-Rail-Protective-Compatible-Rech... One of the reasons I still like my phone is because of that case. I wish there was something similar for another phone. The external batteries also have microUSB in and out, so I can charge friends' phones too.