Day. Ask them for compensation. No, go and test it. Then test it. Whether man-made or machine-made. . . No, sue him, NND. If you have only bought it for a few days, there is an 80% chance that there is something wrong with the machine. Go to the official maintenance department of mobile phone to check it. Let them issue a certificate and force the seller to change it. If you don't change it for me, I have evidence to complain about you.