If I contract a company to do periodic lawn care, do I need to stop them from work if they show up on Shabbos? If their job involves shoveling the driveway to clear away the snow every time that it snows (and isn’t just a random day that they show up) do I need to stop them?
Ideally you should not have them come on Shabbos. If there is no choice you can be lenient.
All the best
Biur Halacha 244:1 (ד”ה או) writes that this question remains unresolved. However, Igros Moshe OC: 3 Siman 35 concludes as answered above.