Dr. White was a cosmetics specialist in the Red City. Black was one of Dr. White's customers. Since Black had moved far to the Pink City, he instructed his staff, Grey, who happened to be visiting the City Red to take 20 packs of face whitening cream produced by Dr. White and the strawberries ordered by Black during Dr White's holiday in London.

On the way home from City Red, Grey had to stop due to the worst haze. He was told that Highway to Pink City had been closed to all traffic for two (2) weeks. Gray had tried to contact Black to inform about the situation and also to get Black's instructions. Unfortunately, Black had switched off his mobile phone. Grey had tried to contact the Black's office but had been told that Black was attending a meeting in Paris for three (3) days. Grey later left a message to Black's mobile phone but Black was too busy to read it. During the suspension, Grey had been living in a motel and met Brown. Brown who also suffered from skin problems asked to buy whitening cream that Grey had and Grey sold all of them to Brown. After two (2) days, the strawberries started to rot. To avoid losses, Grey sold them at a local market and saved the profits for Black. After returning from Paris, Black read the news about the incidents at Highway at a Pink City. He was very angry when informed that all his belongings had been sold. Black blamed Grey for failure to comply with his instructions and he wanted to take a legal action against Grey.

Solve the above problem based on the principle of agency law. Support your answer with relevant sections and case-law/relevant examples.