This idea has been tossed around in other forums, that mediabase has intentionally blocked out all non-paying viewers to their charts...it is possible, i mean its not like mediabase is broken you can still see their Top 40/50 chart and the jump and taking off charts work.
We may never be able to view the full mediabase charts again
But you can sign up free to AllAccess and view the Top 50 of all the formats!