When they flash me it feels like some good 4-5 sec, but when I do i get insta-killed as if they weren't flashed, or they are flashed for like 2 sec I don't know what am I doing wrong

I had a ranked game where 3 people on my team wanted my gun skin (elderflame vandal) , I thought nothing of it just some pretty match chat and I said oh that’s cool I own it . The tone of the match changed instantly to them begging for my a...