Arcade Machine Repair

I sent three trade Stimulators out for repair in October 2013. Two came back full repaired. The third one was returned un repaired early in 2019. I have tried to get my deposit back for the repairs but so far have only received $300 of my $600.00 deposit> Have texted Doug Fox about he balance which he promised would be sent. But now he will not even answer my calls or return a text as to when I should receive my refund so I can send it out and get it repaired.