Panny (21 years old) entered into an exclusivity contract with Stars, one of the largest singers agency in the EU, when she was 17.

According to the terms of the contract, Stars responsibility should be to make reasonable efforts to secure and or negotiate Pannys participation in entertainment, concerts, recording, stage, film, television, literature and related fields around the world, including but not limited to sales, advertising, Interactive media or any other existing or future technologies. Stars may provide suggestions and suggestions for the career development of artists.

According to the contract she would, for a period of five years, obtain all of her singing works through Stars and refrain from singing for any other agency other than Stars until the contract expired.

A friend invited her to perform at a party in London on the weekend, and she accepted the invitation. The invitation letter was sent directly to her, not through her agency. The stars discovered her invitation and asked her for a commission for working in London.

In order to attend the London event, she had to decline a concert in China organized by Stars. So, Stars now wants to sue her for their loss of commission in China and breach of contract.

Please advise Panny and answer the following legal questions ( Please fully explain the answers as much as possible):

(1). Is Panny under any obligation to pay a commission to Stars for the London event?

(2). Whether there is a breach of contract between Panny and Stars?

(3). Whether Stars had mitigated damages for their loss of commission on the job in China?

(4). If the event Panny has to pay damages to Stars, how the damages will be assessed?