Note 2 keep restarting

Hi guys, these few days, my note 2 had this problem. Occasionally, it will keep restarting and the battery indicator will show that the battery has 5% battery left, even though there is at least 50% power remaining in it. At times, it will show that there is no SIM card detected. I'm not sure if it's a phone problem or is it because I use 3rd party battery(anker). Does anyone face similar problem?

Thanks