According to the Australian Consumer Law (ACL), a contract was established between Mary and Lianne for $9,500. As per Section 3 of ACL, Lianne is considered a consumer as the value of the contract is less than $40,000. Lianne had specified requirements for the party, including Malaysian-themed food and drink, live Joget and Zapin music, and a room for dancing. However, Mary failed to meet these expectations by supplying Russian-style food instead of Malaysian cuisine and an extremely cramped boat with no space for dancing. As per Section 54-56 of ACL, Mary is responsible for honoring the consumer guarantees and providing goods that match the description. Additionally, Mary made false and misleading representations about arranging a professional and stylish party, which is in violation of Section 18 of ACL. Therefore, Lianne can sue Mary under ACL for violating sections 18, 29, 54-56.