What is the ruling on purchasing a car from a company that sold it after its lessee was unable to pay its ownership installments?

Leasing ending in ownership has permissible and forbidden forms. If the contract fulfills the Sharia conditions, the car remains the property of the company, and the rulings of leasing, then sale upon ownership, apply to it. You are permitted to purchase it. However, if the contract is invalid due to the simultaneous presence of two contracts (leasing and sale), then the rulings of a فاسد (corrupted/invalid) contract apply to it. The commodity returns to the company, and the company must return what it received, and you are permitted to purchase it from them.