auren,
Thanks for following up with those additional details.
Next, try removing any protective films or cases that might block the volume buttons. If you haven't already, we also suggest checking for debris or dirt around the buttons. This article explains these steps in greater detail:
If a button or switch isn't working on your iPhone or iPad
Also, head into Settings > Accessibility > Audio/Visual, then slide the audio volume balance slider all the way to the right. Do the same thing by moving the slider all the way to the left. Do you hear sound as expected?
If not, we recommend getting the iPad into the hands of a service center. We strongly recommend booking an appointment since walk-ins might not be accepted, and you might be able to find locations and book an appointment online here:
Find Locations
If you're in a supported region, you might also be able to view and book appointments using the Apple Support app:
App Store Preview
Before heading in, here's how to prepare for your visit:
Get your iPhone, iPad, or iPod touch ready for service
Have a great day.