With a Lite account, you are only able to add your details to one device at a time - for example, an iPad, but then not also your Google Calendar.
You can change your device once every few months (e.g. if you purchase a new device), but if you try and add a second device more often than this, you will get a message displayed on your calendar reminding you that you have added too many devices.
Please note that this restriction does not apply ot the full account. In addition, if you choose to upgrade to a full account, your unused 'lite' account time will be transferred over to 'full' account time at the approporiate rate - i.e. you will not lose out at all.
If you do not wish to upgrade to a full account, though, then if you remove your subscriptions from all your devices, and then raise a support request, we will reset your account so you may then choose which single device you wish to use Roster Buster on. If you do not remove Roster Buster from all your devices first, then (for example) your iPhone may try and download the information automatically, thus choosing 'itself' as the one device you want to use.
To find out how to delete Roster Buster automatic links, please see elsewhere in this FAQ section.