This happened with me, without prior notice. I was writing as a freelancer and was getting paid as well. All my contributions are no longer visible. Though I save them on desktop, still it is so disappointing not to see them online.
Which site closed? are you sure it closed or is the website just experiencing some difficulties? Regardless, it's always important to have backups of your work and it sounds like you do. If these people still owe you money, I would contact the company directly. (do a whois search on their domain and it should give you contact info)
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