Which action is necessary if you want to stop receiving newsletters from Sage?

To stop receiving newsletters from Sage, leaving the box unticked during the subscription process is necessary. This implies that, if there is an option or box for subscribing to newsletters, by not selecting it, a user expresses their choice not to receive such communications. It is a standard practice during sign-up for various services to give users control over the types of correspondence they wish to receive.

Unsubscribing via email is often a method available after initially subscribing, making it effective but not the necessary preventive action before receiving unwanted newsletters. Similarly, contacting customer service or deleting an account may be options but are not the most direct or proactive measure; they typically involve more steps and may not directly address the issue of newsletters unless outlined specifically by Sage. Thus, leaving the box unticked is the most straightforward action to avoid receiving newsletters in the first place.