What is the ruling on purchasing a car in installments from an agency that imposes an interest rate ranging between 11-20% on the remaining (deferred) amount, with the rate increasing as the number of installment years increases?

If the company owns the car, has acquired it, and taken possession of it through purchase, then it is permissible for the company to sell it by installments, whether the entire price is deferred or a part of it is cash and a part is deferred, as long as the price has been agreed upon. This is because it falls under the category of lawful trade that Allah has permitted, as He says: (And Allah has permitted trade and forbidden interest).