Whoops, fixed and fixed! And regression tests added.
I had made a silly, silly mistake when I went to restrict numbers longer than 7 digits from the "free plan", I had at the same time disallowed digits larger than 7 as being "valid digits", so anything with an 8 or a 9 had been "invalid".
Also, I broke something, maybe in the caching logic. I tried 99999999 then 999999 then 99999 and down, and now I'm currently getting.
also fails on 8.