Case:

I made an invitation to treat in newspaper to sell a car for $32,000 in 15^th of July. Then someone offer my car $38,000 and I agree with him a deadline to pay until 2pm on 22^nd of July. He said that he wants to see bank manager first to ask when the money available before I give him a deadlines to pay. I said if he did not pay until deadlines I will sell my cars to another person who willing to buy $40,000 but this person is in another city.

1. He send me an email on 18^th of July for ask me if I can accept the payment for instalment over the next 5 weeks. I read the email but I did not respond.

2. Then he send me another email in 20^th of July and said he needs 4 more days until 24^th of July and he will be able to pay $38,000 in one payment also he already deposit $1000 to my bank account. He said he will contact me soon. I read the email but I did not respond.

3. He is going to overseas for business trip.

4. I didn't have any contact from him until 23^rd of July, so I sell my car to another person that is offer to buy $40,000 in 23^rd of July.

5. On 25^th of July I send an email to him to let him know that I already sell my car and it's no longer available for purchase, and I will refund his $1000 deposit.

Question:

1. Is there any valid binding contract between me and him?

2. Did I accept his offer to extend the payment from 22^nd of July to 24^th of July by not respond his email?

3. Did I break the contract about selling my car to another person?

4. Can he assume that I accept his offer by email while I did not respond his email?

Can you find a correct case authorities and section numbers of legislation also relevant law to resolve the legal problem?