Where did I say it was a Ponzi scheme?  I simply mentioned Ponzi scheme as an example of a scam that gives returns for awhile, there are other types of scams that will do the same.

And stopping new purchases doesn't prove anything in terms of whether or not it's a Ponzi scheme.  For all we know, you're stopping new purchases because you've reached the point where you can no longer support a Ponzi scheme.  Again, not necessarily stating that this is a Ponzi scheme, just pointing out that you haven't said anything that would be inconsistent with one.