Computershare Trust Company review: Employee stock purchase program

I am previously employed by MasTec and I participated in an employee stock purchase program through Computershare Trust Company based in Louisville KY. I tried to cash out my shares a few years ago and they told me there was a waiting period on that since I left the company. No problem, fast forward to 8/22/2022, I need to cash out these shares and the last communication came from them was on 30 Jun 2022 stating I have no shares and $0. How is this possible? I just want my shares that I paid into while employed with MasTec.