I've deleted reseller and removed his IPs from WHM (except from 'Manage Nameserver IPs' where it didn't allow me, because they are still registred with domain registrar).
After that* - ALL domains on server stopped to work! I am talking about my domains, under root account, which are using my nameservers.
Some results from dnsstuff and similiar:
Timed out getting NS data from parent server
Traceroute: Don't have a destination IP address
Ping: could not determine the IP for domain
Note that I didn't touch any other IPs/nameservers - didn't touch anything at, all except reseller and his IPs/nameservers which were deleted. And all this was done from WHM - nothing was edited from shell...
Two hours passed, still no help from SM support...
*I suspect this caused error. In time before the problem, I also copied 3 accounts from another server, and created one domain as addon domain. But these are usual stuff, so I shouldn't suspect it?