Submitted order cancellation

[iuakash]

3 Days back, I get an service request from buyer against my buyer request.
after long discussion he agreed to time line 3 Days. I submitted sample same day and later he asked for some new option.
due to not get official order, I just submit my gig and request him to accept. In that case It’s counted as fiverr.
After a while he accepted and countdown start. after sometime, he asked to cancel this work order. Some how I missed this request and I submitted my work.
Finally he disagree to rcv this and again asked me to cancel this work order.
I search and tried to cancel this order. Fiverr shows this is "submitted"
Now How can I cancel this order request without any bad experience both buyer and seller?