My home helpers do not have a work phone. What can I do?

You cannot require the use of a personal phone without a legal or contractual basis. Provide a work device, or arrange for clocking at the depot on a clocking station (linked to the “Depot” place), supplemented by corrections with a reason. A person without an email address can be created without an account: they clock in only at the clocking station with their QR code (or employee number) and PIN code.