At times the Mods will dispense Tokens to compensate a user that needs to run a number speed tests or has other issues.
It may be a good idea to go to your dash board and lo in. Click the "billing" tab and click the "unbilled activity" link to ensure that someone in the household didn't purchase some tokens without your knowledge.
Great question ! Gwalk has a good point- check with anyone else in the house to see if they purchased first and check your balance. If not, they may have been as BirdDog and GabeU mentioned, provided by an agent for troubleshooting. Let us know if you have any other questions.
Also just to add. You would not have been contacted beforehand. They usually just add them in. If you do not see any recent token purchases, and you are still not sure, using them will not bring any extra charges. Removing them is not possible. So they're yours :-)