[2022] Steam deleted my licence

Hi guys, I bought this game 6 months ago, and I didnt play it for last three. I wanted to play it for my vacation little bit. But it's not in my steam library. I can't find it, only I can purchase it. When I try activate the code that I have saved in my email account I get "This key is used by different account" error. I tried contacting team support but no avail. Can you help me?