Mugen Power Super Extended 5500mAh Battery for Samsung Galaxy S4 with Black Door Cover

I liked this product at first and it worked well for extending power. However, after a year I noticed that my phone seemed distorted and the back cover no longer closed properly. On opening, I found the Mugen Power battery was swollen as evidenced by the attached photos. For example, the left photo shows clearly the curvature from swelling on the battery face; the middle photo shows the back of the battery clearly pulling apart and showing white seam on side. I am worried of potential fire so took it out. My purchase of $89.99 is lost. Fortunately, I saved my old battery and phone cover; the phone itself seems to be working O.K.

My S4 lasts for 2 days max now.1 day plus few hours with watching movies and listening to songs with bluetooth and wifi on.Great product!