Due to the way our systems are configured, you are "hard limited" to the amount of bandwidth allocated to your particular package and are therefore unable to use more than you have. Once you approach 75% of your bandwidth usage, you will periodically begin to receive e-mails informing you that you're reaching your bandwidth limit and steps must be taken to ensure that you don't hit or go over this quota. This should provide plenty of notice and pre-warning so that you can take the appropriate steps to upgrade your account.
Upgrading your account is easily accomplished using automated processes via our client area, and full instructions can be found here:
If you do not upgrade your account and your site reaches the bandwidth quota allocated to you, your website(s) will cease to display your website files and will in place display a "Bandwidth Exceeded" error message. This message will clear either on upgrading your account, or at the start of your next billing cycle - when all bandwidth measurements are reset.
If you reach your maximum disk space quota, then you will not be able to upload any additional files to your website. This may cause problems with dynamic scripts if the uploading of content is necessary. Additionally, if you are hosting your e-mail with us, you will not be able to receive new messages to any mailboxes on your account.
As with the bandwidth notifications, at 75% disk space usage you will periodically begin to receive warnings that you are approaching this limit - leaving you adequate time to make arrangements to either reduce your usage or increase your package.