Sound Declining in Left Huawei FreeBud 4 Earphone

I bought Huawei FreeBuds 4 earbuds, and within a year, the sound in the left earbud started diminishing, even fading away completely. Despite not using it constantly, the device is still under warranty. When I contacted customer service, they claimed the earbuds were dirty. I assured them that I regularly clean them with cotton buds, so that couldn't be the case. They insisted I send them to the service center. After 10 days, the service asked for 250 TL to clean the earbuds. A friend bought the same model and they demanded 550 TL from them with the same excuse. The earbuds cost only 200 TL, which is outrageous. I will never buy anything from this brand again. They are fooling people by claiming everything is a user error.