How can I properly repossess a vending machine that was financed to a customer who placed it in someone else's private property?

The question

The vending machine has been financed to a customer who has signed a contract and agreed to pay the respective payment every month. As per the terms, the equipment has to be repossessed should the customer fail to make the payments. However, the machine is placed in a private property who's owner is a third party. How can we lawfully repossess the machine should the location not allow us to remove the machine or not allow us to get into the location to extract?