Same things happens to me yesterday.
After I deliver my bass track, done some revisions the buyer ask to cancel.
I wrongly press the "accept" button, cause the layout is really bad made, with the accept button highlighted in green, as for sending a message.
I immediately send a message to the support and they told me that they can't do nothing.
So the buyer have my bass track and I get not payment!
After being on fiverr for 3 years as a PRO and TOP RATED SELLER, I am really thinking about leaving the platform.
The balance of protection between seller and buyer is so demoralizing.
And they keep taking their 20% of commission without doing nothing to protect the sellers.
What a shame!