ISP billing bollocks
Several moons ago Pipex were my ISP of choice having established a decent service and also as they were one of the early UK ISPs to jump on the broadband wagon (I still recall sending in my trusty US Robotics 33.6 whistler and getting back a shiny Fujitsu ADSL modem in exchange).
Anyway, I migrated from them (cleanly, MAC code etc) to Nildram, then Be and now Plusnet.
However, around 18 months after leaving Pipex, I saw a direct debit going out of my account that I didn't recognise for a couple of hundred pounds.
I did some digging with the bank (Abbey, in their pre Santander guise when their service was resonable) and found that Pipex/Tiscali had taken the money.
Following up with Pipex/Tiscali, it transpired that although I had migrated away cleanly, some part of their monolithic billing platform hadn't got the relevant memo. It still thought I was a customer and should be paying them. Apparently they had a "sweeper" team that would look at accounts such as these and then follow up on getting the money.
In this instance, they had my account details still on record (I switched my payment to Direct Debit just before leaving them so I could cancel the instruction myself). Several broadband related sites at the time were rife with horror stories about attempting to rescind card payment authorities when leaving/migrating and often advised customers to switch to DD as they left to sidestep this issue.
Pipex had setup another Direct Debit against my current account without my permission or knowledge using the historic details and then used this to obtain the payment in question.
I contacted their high profile incident team and let them know in no uncertain terms what I thought of their behaviour (tantamount to fraud in my opinion) and ensured that I got my money back along with some extra for my time/compensation.
The stupidest part was, my old user account/details still worked on their legacy customer site and I could clearly see where one system said "long gone", vs the other one that cluelessly thought I should still be forking over my hard earned each month. So, if I could see that, why the feck didn't their "sweeper" team? Doubly ironic when you consider that they were supposed to be in the communications business.