Help!!! Humane Society is trying to steal my cat!!!!

My cat Duke went missing on Oct 2 due to fireworks. Ive been searching for him night and day. I even sent a poster to the society on Oct 4 and my post was verified on Oct 17 from Spca. My information on the microchip has been updated as well. I was on facebook checking to see if my cat was found and instead I see a post of my cat up for adoption??? I comented and left my number and posted a missing cat poster and they then blocked me?? She called me and said she wasnt able to get a hold of me and said she didnt want to give me back my cat? Why I thought the point of microchipping was so I would get my cat back quickly. Help I love and need my cat!!!! My son was killed in a hit and run at the age of 22 on Sept 21,2021 and I'm so gratefull that I had Duke. I really truly need my bubbies!!! PLease help!!!!