Sennheiser 458 BT Right Earcup Has Low Volume and Severe Crackling

I purchased the Sennheiser 458 BT headphones from Teknosa, paying five times more than comparable models simply because I wanted a high-quality product that I could use reliably for years. However, when I tried to use the headphones again today after leaving them unused for an extended period, I discovered that the sound from the right earcup was barely audible and accompanied by severe crackling.

The device developed this problem on its own, without being subjected to any impact, drops, or liquid exposure. After doing a quick search online, I found numerous people reporting similar issues with the same model. Furthermore, the warranty expired only three months ago, making it unacceptable for the headphones to develop such a serious fault so soon afterward.

I have been thoroughly disappointed by the quality and durability I expected from a brand like Sennheiser, especially considering the high price I paid. I believe the product is defective. Even though the warranty has only recently expired, I request that Sennheiser resolve my complaint by providing free repairs, a replacement, or another reasonable solution.