You're right, if you have any close matches who aren't J2, they're not really matches. If you have any suspected relatives who test, that will quickly weed out non-relatives.
I'd guess the delay was because you're in a rarer haplogroup. They can reliably estimate the haplogroup if there are already plenty of prior testers with similar haplotypes. Since they guarantee a haplogroup designation, they probably ran a backbone test to verify your results. That's the only way they can confirm your haplogroup, unless you had a Deep Clade test or appropriate individual SNPs.
I hope you have some matches, I have no close matches beyond 12 markers.