After studying the question mentioned above, the answer of the committee is as follows: (Part No. 13; Page No. 163)
The first passage of the question asks about the ruling
selling a car by installments by paying the first portion immediately. The rest of the installments will be deferred. Then the buyer sells it to another person and then pays the first installment from its value. Then he will pay the rest of the installments in their due times. This kind of transaction is permissible. But you are not permitted to hold a contract with the buyer before acquiring the car from the one who sells it to you.
As for the question that says:
"What is the ruling on buying a commodity from someone other than the person who buys it from you in a deferred payment?", it is a permissible transaction if there is no agreement in advance for this.
The third passage of the question talks about
the ruling on being a deputy in selling a commodity for a person who buys it from you in a deferred payment. This kind of transaction is permissible if the buyer acquires the commodity completely from you after buying it. And Allah knows best.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.