I just robbed the same way and feel so demotivated
A new buyer with no reviews or previous buys placed an order, I did the work, sent him samples, he said he likes them but needed a few changes which I did.
Soon after delivering he tells me he can not accept the work simply because he has had divided feelings about it (He states poor quality as reason to cancel), but I declined
I ask him what exactly is wrong with the work then he sends another cancel request stating (seller cannot do this job). I declined again
After I contacted support, they told me to keep engaging the buyer until we reach an agreement, but strange at the same time they canceled my order and refunded the buyer, but my support ticket is still open and Fiverr is asking to me to update them about the progress of my disputed order. I just don't get this