If Eligible sent confidential data to a contract designer for the purposes of a mockup then they deserve everything they get. I don't- for a second- think that they did.
Maybe the designer is misleading us all, and there's a very good reason with the company are reluctant to pay $780 for some work the designer thought they'd asked for. But surely in the field they've chosen, reputation and appearance of trustworthiness have orders of magnitude more value that this spat?