Your Signmee account stays with you forever. You will always have access to all the communications you have received and responded to. When you leave a school or end a business affiliation (i.e. your child moves on to secondary school), the school/business can remove you from the contacts list. The school/business may wish to keep you as an active contact to provide you with future communications where relevant.
Individuals can unsubscribe (deactivate) from any business in Signmee by navigating to 'My settings'.