Tan has appointed Zek as his agent to do the following:

i. To sell 100 bags of flour at the price of $ 4,000 to Zizimart

ii. To buy 20 kilograms of sugar from Morah Store

Upon reaching Zizimart, Zek discovered that the shop would be closed for 7 days. Without getting further instruction from Tan, Zek sold the rice to AA Supplier for $ $3,500. Later, he bought 100 kilograms of salt from Morah Store. As a principal, what can Tan do when Zek, as the agent, has exceeded his authority?