Problem with a client

[9cfb3cc1]

Hi, 
I have a contract that I encountered an issue for the first time. We were agreed on a project that should be on a rolling basis in a time interval. They didn't send the task for weeks and then suddenly they sent the all files in 2-3 parts and determined impossible deadlines. I did what I could and send them the files as I completed. After that I waited for the payment 2 weeks + 1 week. Once I got the payment from escrow, they said that their client sent feedback and I should do the work from scratch. It's again suddenly and they expected it in 2 days... I said this isn't doable in two days, I won't do it and don't accept these conditions. I haven't heard from them since then. Today, they showed up again and requested to do me the work from scratch. I won't do the task again. It seems 32 days passed from my submission. What is the solution here if I don't do the work again?  What would be happen if I end the contract? There is no active milestone. Would they be able to take refund in these conditions? I made the work. They had the time for asking review. Do I have to pay them back? Can they ask refund?