My Anker Liberty 4 Pro's Right Earbud Died, and I Can't Buy a Replacement

The right side of my Anker Soundcore Liberty 4 Pro earbuds completely stopped working about a week ago. The right earbud won't turn on at all and produces no sound.
Since the product's warranty period has expired, I no longer have a technical service option. However, even though only the right earbud has failed, I can't find just the right one as a replacement part — they're not sold individually. Because of this, I'm unable to use the still-working left earbud and charging case.
I am requesting that Anker offer the right earbud of the Soundcore Liberty 4 Pro model for sale individually, or provide me with a solution for this issue.