Database to see who has/hasn't been

Database to see who has/hasn't been

Cancelled

Job Description

I teach fitness classes and am looking for a system that will do the following:

When people come to my classes, I'd like them to be able to sign in using my tablet. I'd then like to be able to see on the 'back end' of the system who has been to each class, and - importantly - who hasn't been. I'd then like to be able to email all the people who haven't been to class, inviting them to come back again.

This is the kind of thing I'm looking for.

Can you help?

Jonny :D