Hi Beans Bee,
Thanks for writing in! Sorry to hear about the troubles but would be happy to help!
Tony A - Community Support
Hello Beans Bee,
Thank you for letting us know what you tried.
Since this is also happening with other devices, we'd suggest contacting service over the phone for a replacement.
If you go HERE, select your region, scroll to the bottom of the page, choose "Contact Us" and a phone number will be displayed.
Let us know how everything works out.
Joel - Community Support
There IS a balance adjustment in iOS 12. Go to "Settings"-> "General"-> "Accessiblity"-> and scroll down to the "Hearing" area and you'll find a balance slider.