Thanks for contacting us and sorry for the issue you’re experiencing.
It’s very weird that the sliders were deleted without anyone’s intervention. There might be a third party plugin that would have caused this. Kindly check out your site logs and trace that action to established the cause of deletion and let me know.
To set up Theme4Press Slider in evolve, kindly check out this article for instructions: https://theme4press.com/docs/setting-up-the-sliders/.
I hope that helps.
Please let me know if there’s any other problem, I’m happy to help.