Without any reason buyer want to cancel order …what can i do now ?
If you did the work you promised, say no, and decline the cancellation request. If you did the work, you should get paid for that work.
I have completed that order
Then say no to the cancellation request. Why would you refund a completed order, and let the buyer have your work for free?
he told me that i needed cancel order
He would be wrong. You don’t need to cancel an order that was already completed. Like I said, if you cancel a complete order, you are giving your work away for free, and you wasted your time completing work that you won’t be paid for. Your buyer does not deserve a refund just because he demands that you give it to him. Say no. You did the work; you should be paid for that work.
Thank you for this great advise