Are failures cached?

[Jeremy C. Reed]

You may find some of your answers in RFC 2308 and in the ARM.

http://www.faqs.org/rfcs/rfc2308.html
http://www.isc.org/sw/bind/arm94/Bv9ARM.ch06.html#Setting_TTLs

"The last field in the SOA is the negative caching TTL. This controls how 
long other servers will cache no-such-domain (NXDOMAIN) responses from 
you. The maximum time for negative caching is 3 hours (3h)."

(As for taking a couple days to resolve your problem, I don't know.)