You should talk to a lawyer about this.  Depending on the facts, it may be possible to cancel the policy now, and get your premiums back, if you can convince the insurance company that this wasn't your fault.  That might not be as easy as it sounds.  You might have to go after the sales agent, if he or she wasn't an employee of the insurance company itself (this makes a very real difference);  what the agent did was unlawful, and if proved could endanger his or her license.