Answer:
Bill shall win the case, even when he has a fault but that is not relevant.
Step-by-step explanation:
In case Mary do not want the pair of shoes then she shall reject the pair, and pay the liability as stated in the contract, in case of fault by the party in the contract.
As she has many metal pallets also the fact that Bill delivers the shoes along with metal pallets and not with wooden pallets, is not a major default for the grounds to be sued by Mary.
As this clearly do not make any fault in the quality of shoes delivered, time of shoes delivered etc:
Thus, Bill shall win the case.