The thing to keep in mind is that Social Contract Theory tended to be very powerful within Enlightenment era political discourse, which raises the question: what does Social Contract Theory actually entail? That's probably the key to this entire question. Social Contract Theory essentially states that governments exist to serve a purpose, and it is in this that any government can have legitimacy. As the words "Social Contract" state, this foundation is based in a kind of contract, between the rulers and the ruled. From the context of the American colonials, they saw themselves as British citizens, and this guaranteed them an equal share to the same rights and privileges enjoyed by all other British citizens. This was joined with a context in which, for generations, British oversight in the colonies had been largely limited (in terms of taxation and enforcement of British mercantile law). With this in mind, consider what might have defined that original Social Contract as the colonists would have seen it.
After the end of the French and Indian War, there was a change in British colonial policy. Heavily in debt, they started to become much more interventionalist. I would suggest looking into some of the Acts passed by Parliament during this time period (consider, for example, the Sugar Act (1764), the Stamp Act (1765), and the Townshend Act (1766)) as well as the implications of an increased military presence in the Colonies, or, if we were to look later in this time frame, the Intolerable Acts (1774). I'd also suggest looking into the Declaration of Independence. How would you view these instances, from the lens of Social Contract Theory?