Data blocks are applicable to older plans only and are no longer turned on by default or available for current plans.
Data blocks help you avoid your normal excess data rates, which can lead to hefty bills.
Data blocks charge $10 for every 1GB (or part of) you go over your included allowance as opposed to your normal excess rates which could equate to as much as $40/1GB. You can check to see if you have data blocks turned on in My Account. You will see a message saying 'Additional Data is $10/1GB' under the service. You can turn it off here as well but we strongly recommend leaving it turned on data blocks as it will help you avoid bill shock.
The option for $10/1GB Data blocks will not appear in the self serve portal for current plans.