Tel3 Advantage review: Need the reimburse of my money

I have been using "Tel3Advantage" for ten years or so, more or less without problems. Suddenly the access numbers don't work anymore, neither the service hotline. I still have a substantial credit (about $50 on my accoun to make international calls). For the past few months none of their local access or toll-free numbers have been working, which I can't access anymore, the login to the website is gone. Actually the whole website is gone.
I cannot make any calls; cannot contact customer service by phone or email or even access my account. Any help would bd greatly appreciated.

Thanks for your attention and I look forward to hearing from you very soon and to solve this issue.