Have you had the chance to try repairing Apex Legends to see if that makes any difference at all? If you're playing the game through Origin you can repair it by right-clicking on Apex Legends in the Origin Library and selecting the Repair option when the menu pops up.
If you're running the game through Steam try verifying the integrity of the game files to see if that helps. For more information on how to verify the files check out the Steam Support website. Let me know if you're still having the same issues with your voice chat afterward. Thanks!