Data blocks help you avoid your normal excess data rates, which can lead to hefty bills. By having data blocks turned on, you will be charged $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. If it is turned on, you will see a message saying 'Additional Data is $10/1GB' under the service. If it is not turned on, you can turn it on here as well. We strongly recommend turning on data blocks as it will help you avoid bill shock.