Hi, my Galaxy Note 4 is having a weird issue. I get a the "No signal Notification" (The No-Entry sign) when I do have signal. But my problem is, whenever that notification appears, my phone gets extremely laggy, and dies within a minute! And if I plug my phone in, the battery goes all the way down to zero, then only starts charging. Also, unless my phone is on charge, no matter what percentage it is on, it dies in about 30 minutes. Does anybody know how to fix this?