I need help writing written responses for this, citing relevant cases and legislation only.

Case Study 1:

James owns a small business that sells highly durable watches for hikers and manual labourers. He decided one day to take out two advertisements to entice customers to his products.

The first is a picture of the watch with the phrase "This watch can withstand anything you can or your money back for a limited time only!". Three weeks after seeing the advertisement, Kate's watch becomes waterlogged and malfunctions during a particularly heavy rainstorm. Kate approaches James for a refund and he refuses.

The second advertisement is a television commercial with a voice over that states, "For every friend you refer to buy a watch, you can earn $10.00 cash on us!" The commercial shows images of a young man speaking to friends as a bank balance flashes on screen with higher and higher amounts up to $100,000.00. Natalie manages to refer 120,000 people to purchase watches through her Instagram page and seeks to claim the full cash amount. James refuses.

Advise Kate and Natalie of their rights using relevant case contract law

Case Study 2:

Mustafa decides he wants to encourage his son Karim to stop playing video games. Mustafa offers to give Karim a car if he "stops spending too much of his time playing on his Xbox over the next month". They sign a written contract confirming this arrangement with the exact language above.

Karim stops playing video games for three weeks. Mustafa tells Karim that the car is actually a vintage Mustang worth a significant amount of money and in great condition.

One week later, Karim seeks to enforce the contract for his Mustang. Mustafa reveals that the car is actually a 1996 Toyota Corolla worth about $700. Karim demands a Mustang under the contract.

Advise Mustafa using relevant case contract law