Client ask for a refund

[#1]

Hi,
This is my first time writing to upwork with a client issues.
We started to work about one month ago! As usual, I completed my task and give showed him. He said he and his team members all are loved my work and ask for some minor revisions! I did that too.
In this time, clients response time was horrible....But he went in complete offline when I submitted my revisions, so after 5-6 days, I submitted my work through the contract (submit work for payment) option and waiting for this reply as I know, if he didn’t came back to me, my payments will come about 14 days later! Because of my hard work, I really deserve that.
But after 7 days of my submission, this morning he came out from nothing, and says he want a full refund and end the contract!!
What should I do?

[#2]

The first thing you should do is communicate the client and ask them why they are requesting a refund. 

Of course you can decline the refund or give it, but really you should start with just asking the client with why they want a refund, and attempting to address whatever the issue is. Find out why they want a refund (give them like 24 hours) and then go from there. If they don't respond, I would simply decline the refund request and send a message that you'd like to discuss their request but cannot approve it outright with no information. 

[#3 · Accepted solution]

If I Don't refund, he will give me negative feedback! He replied. That was 100$ job, and I Don't want to have any negative feedback, because it will destroy my JSS! Just to say, all people are not same, there are some good guys and there someone like this client! We freelancers are helpless. All the time. Just pray to GOD that, please don’t put anyone in this circumstances like myself. Thanks for your words Amanda.

[#4]

Hi Mehedi, DON'T refund.

[#5]

If I Don't refund, he will give me negative feedback! He replied. That was 100$ job, and I Don't want to have any negative feedback, because it will destroy my JSS! Just to say, all people are not same, there are some good guys and there someone like this client! We freelancers are helpless. All the time. Just pray to GOD that, please don’t put anyone in this circumstances like myself. Thanks for your words Amanda

[#6]

*Carlos