Case:
I made an invitation to treat in newspaper to sell a car for $32,000 in 15th of July. Then someone offer my car $38,000 and I agree with him a deadline to pay until 2pm on 22nd 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 18th 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 20th of July and said he needs 4 more days until 24th 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 23rd of July, so I sell my car to another person that is offer to buy $40,000 in 23rd of July.
5. On 25th 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 22nd of July to 24th 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?