Some of my achievement just reset to 0%

Yesterday I saw my double kill medal was still about 40%, and my killing spree medal was about 30%
But today I checked them again after I finished a matchmade game, I found out they just become to 2% or 3%
What should I do? Where can I report this problem?
I am a little bit angry because I did this hard, but it’s just gone. I saw this happened to many people, too. How did they fix this?

The short answer is that they don’t fix it. Like you said, many people have been hit with this glitch, and not one of them has got their achievement progress restored as far as I’m aware.

So…it means I got bad luck, didn’t I?
I am a little tired of this.
Why happened to me …

It’s not just you mate, we have all be beaten with the ‘reset’ stick. I have over 1,000 grenade kill medals. My progress is at 3/500…I have had four resets so far…