How did you find out about this appointment?
What does the appointment actually say?
Also, does it say you (or someone over 18) needs to be in for the tech visit?
Is the tech for an internal or external visit?
Sometimes tech visits are arranged due to another customer having connection issues and the fault has occured due to another customer doing their own alterations which have affected neighbouring people, and due to the difficulty in tracing the origin of this fault then all local customers are given appointments.
Tech visits may also made due to changes of equipment/installtion of new equipment following package changes.