In March, Comcast disconnected my cable internet service, ultimately due to a problem about overusage (too much "unlimited" data used). While they were hard to get a hold of (or at least someone who had any clue what was happening), you eventually have to call a number where they make you feel you are a criminal, and they won't talk to you: you have to leave a number on your answering machine and hope they call you back while you are able to pick up (and leave you shutoff for as long as it takes). Luckily, I had my cell phone with me when they called me back in the evening and explained "you used too much data in February, and got disconnected as a result".
Ok, great, never mind that unlimited is not unlimited, they were likely correct about the data usage (400GB in a month) so I fixed the problem (mostly an rsync backup script that was doing something wrong and using at 20-40x the amount of bandwidth it should have). Their representative said "you have one month to fix it and we'll resume monitoring and shut you down if it happens again". This was March 14th.
About 6 weeks later, in early April, they shut me down again with no warning or call. I call back after going through the useless 1st level support who wanted me to reconfigure my windows DHCP settings and then said I shouldn't be trying to use the service if I had linux, and I eventually talked to their security staff who said "you had an overusage for March again, so we shut you down for good this time"
Me: "Mmmh, you warned me on March 14th, I couldn't fix anything that happened before you warned me, but fixed it after that date"
Him: "You had an overusage for the second month in a row, we had to shut you down, it's our policy"
Me: "Why don't you look at my usage numbers after you warned me and I fixed it"
Him: "We don't have those numbers, we only have all of March"
Me: "But you know March was almost half over before you warned me, and I had no way to go back in time and make that go away"
Him: "Sorry, it's our policy"
Me: "So, what's the point of warning people if you don't give them a chance to fix the problem. What about the one month grace period your collegue told me about"
Him: "There isn't any grace period, sorry"
Me: "So there was nothing I could do then"
Him: "In your case, I guess not, sorry"

Putting aside the unlimited which obviously not unlimited, it's pretty pathetic that while Comcast tries to do the right thing by warning you and giving you a chance to fix an overusage problem, their braindead-ness and refusal to follow basic logic, causes them to shut you down before you can actually fix the problem.
Good job, comcast!
Verdict: "Sorry, you can't be our customer for 1 year". Considering how they work, I'm not sure I want to be their customer at all ever again.

Until they fix their warning system to match logging cycles, or honor the one month grace period they promised me, and then pretended they never had, I can see how they're going to get many other people shut down that way.
If comcast is actually meaning to give their customers a chance to fix a usage over an arbitrary limit they won't disclose, they have some serious fixing to do, starting by not putting their customers in the criminal/DMCA pile that their regular support folks are not even allowed to help.