Dikgomo Dairy (Pty) Ltd (DM) is a milk producing farm with about thirty (30) employees. Three of these employees are trained milkers (Porschee, Roy and Paul) and the rest work as admin clerks and drivers. Ordinarily, they all work five days a week. DM supplies fresh milk to several clients which include supermarkets and Chocolate Factory SA (CFSA). On average, DM must produce at least twenty thousand (20 000) litres of milk a day in order to meet the demand from its clients. To achieve this, employees use a very sophisticated and modern technology from Lesotho which requires minimal human presence to operate. In other words, one milker can run this. Only the three milkers were trained by the company to operate this technology. On 1 November 2020, DM secured a new client which then meant that the 20 000 litres per day would no longer be enough. During the company's 2020-year end function, DM issued letters to all employees informing them about the new development and advised them that on their return from December holidays (05 January 2021) they will all begin to work one more hour per day as overtime in order to meet the increased demand for milk. While everyone agreed to the employer's proposal, Porschee and Roy refused to work overtime because, overtime would mean a reduced family time and that, it was not in the contract they initially signed five years ago. The employer was unhappy about this and threatened to dismiss them if they continued refusing to work overtime.

Discuss the position of the law with regard to Porschee and Roy's refusal to work overtime and DM's threat to dismiss them. Your discussion must answer whether -

Porschee and Roy's argument can stand in court and why.

DM can lawfully dismiss them if they are persistent about not working overtime and what will be the basis or grounds in law for its decision.