After 64 successful gigs with positive reviews i bump into one particular buyer

[solmio]

Whose instructions I followed to do a voice over. He did not like it and stated it was done by a machine and not a person. So i re read the script after i received his as a guide line. Sent the buyer the audio one with processing and the other without, totaling 3 audios. We exchanged emails that stated our cases yet he already had accepted the order, paid for the audio but then contacted fiver and cancelled them thus getting a refund and still having my audios.

Any suggestions on what to do? I hold fiver accountable for not reviewing the case and just going into my pocket and refunding my hard earned money. What guarantees do I have that the buyer will not use my audios?