Cottonking — Poor quality of trouser [Black colour]

I am consumer of Cotton King since last 7 years. I am using only Cotton King Shirts and Trousers. I am very much happy and satisfied with fittings and quality.
But this time I am very much surprised @ poor quality of trouser. In COVID-19 situation, for disinfection every where 1% Sodium Hypochlorite solution is used. When I have passed through this spray, my black colour trouser get totally damaged. This trouser I have purchased in Nov'2019. This is happened to only my trouser. Even I have enquired with security people, they also surprised. They have also sprayed the same solution on their trouser, shirts but no any damages to their clothes. I have cleaned my trouser immediately by normal water but mean while in 2-3 minutes it was totally damaged. For your ready reference the photographs are attached.
So, in future also we have pass through such disinfecting solutions for couple of months. So then what to do? Shall I stop to use Cotton King brand??
My friends are also unhappy by seeing this quality.