If you have not already, please post flyers in the area where Stella went missing, and knock on doors. Not everyone is on social media. You might also ask folks to check their security monitors, if they have cameras... Might capture something useful in the footage.
Also remember to check with local animal shelters. And phone to ask their current protocols. I have heard that visiting in person to review their intake logs is the best way to get accurate information.
I hope to read a positive update soon.