Hello fifimargaret.
Thank you for using Apple Support Communities. It sounds like you're experiencing issues with your AirPods. Specifically, your left AirPod is no longer responding or working properly. We can understand how this would be an issue. We also noticed that you're already coming from a helpful resource below:
If your left or right AirPod isn't working - Apple Support
It sounds like you've done a great job in troubleshooting this specific issue. There are two more resources we'd like to share with you below:
If your AirPods won’t charge - Apple Support
If your AirPods won't connect - Apple Support
These resources have a few more additional steps you can try. However, if you continue to experience issues, it might be best to reach out to Apple Support for help. Just in case, you can use the link below to reach them:
Get Support - Apple
We hope this information is useful. Cheers.