Stella,
These are basic premises for listing an Airbnb property and you alone are responsible for understanding how it works. There are hundreds of resources available to you to help you learn, including this entire Community Forum.
That being said, if you only have 2 reservations, use this as a 'live and learn" opportunity. If you cancel, you will be penalized - you can read about this in the Help Center. You can also learn how to turn off Instant Book, how to price your property, turn on Smart Pricing, cancel those resevations if you decide to do so and, finally, add a security deposit, verify your profile, ask for levels of verification prior to booking, and other options. You will also learn how to deactive your account and snooze it if you want to take some time to learn about Airbnb.
You can try to plead your case with Airbnb. Use the search box above to look for the "Contacting Airbnb: A Community Help Guide". From what I can see, you are only talking about 7 days of "low price" bookings and a potential of $150 in fines for cancelling.
Here are some additional resources for you to use to become acclimated to Airbnb and it's process: https://www.airbnb-toolkits.com/my_toolkits
http://www.theglobeandmail.com/news/toronto/toronto-to-propose-airbnb-regulations-as-short-term-rent...
Good luck and welcome to Airbnb.