I’ve had my soundcore since July and has worked great until today. Now it won’t power on
Which sound core are you talking about? Also have you tried using a different cable to charge it? 9 times out of 10 it comes down to the cable being faulty and not properly charging a device thus why it won't turn on
If it still doesn't work after @elmo41683's instructions, try sending an email to firstname.lastname@example.org. I hear they're nice over there.