After the phone "On5 Pro" got updated to Oreo, phone is getting switched off by itself when the battery level reaches 30 or 40 percent.Also the battery bulged which is pushing the screen upPlease help!Thank you

After the phone "On5 Pro" got updated to Oreo, phone is getting switched off by itself when the battery level reaches 30 or 40 percent.Also the battery bulged which is pushing the screen upPlease help!Thank you.