I bought macbook 2 weeks ago and have 2 charge cycles. Yesterday i notice it didn't charge. So i tried usb c and it work well. So the adapter is working fine. Seems like issue with magsafe 3 cable. Is there anyone has face same issue?
I'd go to the Apple Store. Check to see if it will charge on a different MagSafe cable. Either way, you need their help - either a new cable or a new computer.