Looking at things from a safety standpoint firstly
@Shirlz, if the case of your phone is starting to curve, this could be a sign that your battery is swollen. I would therefore recommend that you don't use your device, at least until after it has been looked at. I don't know if a replacement battery as a fix will be possible if your current battery has swollen, as this may have caused some internal damage. I would say that you are probably looking at a replacement device at the end of this.