battery replacement

There is a variety of information here about repairs, battery replacements, and other bits:

• Mac Repair - Official Apple Support

https://support.apple.com/mac/repair/service

..to see if your location may qualify for 'mail-in' service, ask..

• Apple Repair and Repair Status Check - Official Apple Support

https://support.apple.com/repair

As you've described, there should be no charge under AppleCare+ for battery replacement.

Should you need to ask (don't know from here) they also could perform diagnostic on Mac.

Good luck & happy trails!🌞🎣

Battery service is free for all MacBook users with AppleCare+.

To find out more and to get ready for your MacBook battery service:

Mac service and repair