No usage warning mail

[#1]

I've just received a message saying "You've now reached the extra usage limit you set for your broadband service. Your broadband service will be restricted until the end of your billing month."
I thought I was supposed to get a warning message at 80% - is this not the case any more?  It's annoying as I would have been able to adjust the usage if I'd known and it's not worth the £5 for extra allowance when my billing period is only a couple of days away.

[#2]

Hi there, yes you should have had an email about that. I assume you've been receiving other emails from us OK?

[#3]

Exactly the same thing happened to me this month, quite annoying.

[#4]

The usual reason this happens is the limit is exceeded before the usage warning can be sent. On accounts with lower usage this is common, given how fast data can come down these days - @sizzler27, I suspect that's what happened in your case (bear in mind usage runs around an hour behind).
@navman, I'm honestly not sure what happened there though I suspect it may well be the same thing, unfortunately as you're in a new billing month now we can't see the breakdown so can't tell if there was a period of heavy usage there. Would you remember if it happened around a time when you were downloading or similar?