Blessing2 Dusk broken after 16 months of use

Hello! I have been using the Blessing 2 dusk for about 16 months now. Everything had been perfect, but about 2 days ago I noticed that the sound from the left ear suddenly got considerably lower volume compared to the right. I already tried replacing the source, cable, and filters, but I get the same result. The IEMs have always been kept in its case and they have never been dropped or anything, so I am not sure what may be causing the issue. I would really appreciate it anyone knows if there is anything I can do to fix them, as the sound is really bad with this issue now.

Thank you!