Thanks everyone. I think it is going to be okay for me - I had scads of communication with client that I sent to Upwork and it seems like they are more than satisfied I did everything I could. They are going to cover the chargeback. This was a situation where the actual client passed me off to someone else to work with because he was too busy, then that person got too busy but told me to keep working....and then basically quit replying to my questions and updates. These people are the smartest of the smart - MIT, Harvard, etc. Maybe they had a conflict with each other and this is the way they chose to "resolve" it? Anyway, I've asked the Upwork person who is working on it to advise me on what I can do so this never happens again (to the extent possible I guess). I do think Upwork should make it clear in the user agreement/terms of service that just because a payment has been made - perhaps long ago - it doesn't mean the freelancer is entirely in the clear. I would be interested to hear what an attorney thought of the way it is addressed or not addressed now in the user agreement/terms of service. What if everyone did this and you had to give back ALL your earnings?
You are correct Petra, and I'm sorry if my statement was confusing. I have edited my post so as not to create confusion over the matter.
Lee Ann, I can see that you have provided more information and proof that you have worked on the contract and have submitted completed work on your open ticket. The team will use this information to be able to dispute the chargeback. If you have more information you can supply, please update the open ticket so that you can be assisted further.