Hardy Boys Detective Agency hired Nancy Drew to work on an investigation. Nancy initially asked for $5,000 to do the work. However after starting the investigation Nancy realized she underestimated the cost of performance and asked for an additional $2,000 to complete the job. Hardy Boys were short sluffed so they agreed to Nancy's request for more money rather than switch investigators. However when Nancy completed the work Hardy Boys refused to pay more than $5,000 to Nancy. Considering the law of consideration, does Hardy Boys Detective Agency have the legal right to refuse to pay Nancy the extra $2,000? Explain your answer.