From your SMs.to account you can decide what kind of emails and SMS you will be receiving from us by going to Settings and pressing on Notifications:

A very useful Notification is the Low Balance notification that you should receive on your phone as well to make sure your account is never left without funds. Make sure to add an amount big enough so you have time to add funds.

A solution to above is of course to enable the auto-recharge feature on your account that you can find here: Auto-recharge feature