Consider the role of contracts in the following prompt: Alcohol distribution is structure by a three-tier distribution network, where the brewery sells its product to a wholesaler, who in turn sells beer to a retail outlet

Consider the role of contracts in the following prompt:

Alcohol distribution is structure by a three-tier distribution network, where the brewery sells its product to a wholesaler, who in turn sells beer to a retail outlet. Discuss the contracts that exist at each level and any potential problems that could possible occur. 

What is the best argument that can be made that eBay should be responsible for sales of counterfeit products? What is the best argument that it should not be held responsible?