I had Bose QC35 ii and I used then very delicately, always used to clean the pads with cloth after usage, yet they started disintegrating in ~ 1.5 years. Per week usage time was around 3-4 hours max.
I guess they have a fixed lifespan when they are exposed to the environment.
I have read that the human skin oil disintegrates the material. Some recommend wiping the surface with slightly damp cotton cloth to remove the oils etc.
I had ATH M50x (which I stopped using after I got QC 35 ii). The ATH M50x was kept safely in it's original box for maybe 1 year. When I took it out, the pads were completely destroyed. Tiny tiny flakes used to come out each time I wore it. Then I took a toothbrush and scraped all the faux leather material from the earpads. There was some cloth type material under the faux leather thingy, and my earpads have become breathable
Not worth the asking price IMO. 4k per 8 months of usage, it is more like a subscription at this point.
Brainwavz pads last significantly more than the original pads, but they aren't available in India yet (for Ultra).
If I were you, I would buy any 1000-1200 pads from Amazon and see how they feel.
Also, why are they asking you to ship your headphones? They can just ship the lads to you, right? Will save the to and fro shipped and your downtime.