body: A customer walks into a car dealership and buys a car, signing a contract with a down payment and monthly payments. The customer makes the down payment (partial performance). But when he wants to drive off with the car, the dealer says something like, "You can't have it today because we need to do one last safety check. We'll even deliver to your home in a day or to so you don't have to come down again." (Non performance).
  
  
  At the beginning of the next month, the car still hasn't been delivered to the customer, but the dealer asks for a monthly payment.
  
  
  What are the respective rights of the parties? Can the dealer compel a monthly payment without having delivered the car? Can the customer compel delivery of the car, or ask for his down payment back, withholding the monthly payment in the meantime?
  
  
  
title: Can a non-performing party to a contract hold the "partially performing" party to it?