WEX Inc, a global fintech company founded in 1983. We provide tech solutions in corporate payments, fleet management, travel industry, and healthcare. We have hundreds of current openings, both fully-remote as well as on-site. I've been with the company about 3 years. Competitive pay, excellent benefits, and a great work culture. Happy to answer any questions about my experiences.
I think just to preserve brands goodwill, Upwork should absorb the cost (which they have to this point), pursue legal action against the client, and not punish the freelancer.
I don't know the legality of withholding payments for future work due to the freelancer. I don't believe they have a right under the terms to do that, but I would not do any future work for free. That could be a breach of contract on Upwork's part, although haven't read through these terms enough to know that.
https://gallery.ecr.aws/