Hello Alejandrahaz,
For help with HomePod volume, test a normal restart of you devices. The steps below found in the article here will assist: Change HomePod settings - Apple Support
"Restart HomePod
If HomePod isn’t responding normally, you can restart it. You need to be near HomePod to restart it.
- In the Home app on your iOS or iPadOS device, touch and hold HomePod.
- Scroll down, then tap
. - Do one of the following:
- For a single HomePod: Tap Reset HomePod, then tap Restart HomePod.
- For a stereo pair: Tap Restart HomePod."
You can also adjust the volume using the guide here: Adjust Apple TV audio
If you continue to have an issue, reach out to Apple Support directly to further assist.
Contact - Official Apple Support
Contact Apple for support and service - Apple Support
Best.