I am unable to send email today as the IP address you allocate to me is listed on spamhaus.org. It's not my job or responsibility to have your IP address removed or to keep them off the list.
I pay you for a service and I expect it. I am unable to send email so you are thus taking my money and not providing the service. What now? Another 7 days to de-list the IP? (184.108.40.206.)
I can't wait for your normal 7 days, so I de-listed it. It will still take hours before I can send email - get your act together!
(Vodacom had the same problem, but they took the appropriate steps to minimise the problem.)