Ouch that sucks I've been a victim before as well lost a lot of things I wish I could get back even stuff with sentimental value.
Since I got snakes that problem is gone lol , for people to steal a snake in my country is a definite no.
Back to the point I would not try feed her/him for at least another two weeks who knows what that poor snake went through while gone and during the stealing process.
The activeness is not hungry it is still stressed. I would suggest close the enclosure with a towel so its completely dark for about 7 days and also double check your husbandry and fresh water other than that, give the snake some time to feel like a snake again.