Left earbud is not charging on AirPods 2 pro

My left earbud stopped charging since June .. Ever since I took it to the shop while is still in warranty, but after 4 times I went there , they keep telling me that my device passed the inspection tests and everything is fine.. Every time the same thing and 2 days later problems starts again… Please Apple show some respect to your customers and resolve the problem or replace the devices… It is a disgrace for a device nearly 300€ to loose thousands of dollars in buying devices from you …