I had a similar experience when I purchased a software signing certificate from Comodo, exacerbated by the fact that we had accidentally transposed two adjacent digits in the phone number we gave in our listing. It ended up taking about two weeks in all to get Dun & Bradstreet to correct the typo and have Comodo verify the update, and then call us at that number. While the delay was not pleasant, I am glad that they make an effort to ensure that a legitimate organization is purchasing the certificate.