I've just left Plusnet (broadband & phone) after many MANY years of happy service. Only reason for leaving was to get fibre to the premises, which PN don't offer.
Notice was given by BT when I signed up, the switch date was beyond the notice period for PN so they had more notice than I was contracted to give.
My switch date was 10 days into a new billing period. Armed with a cessation date, they still billed the full period which was some 21 days from service end to bill date end. And this is why my criticism starts - if there's a known end date, why not charge up to that date?
OK, that doesn't happen - so now I need to wait another 3 weeks for my next bill date. And then after that another 20 working days (4 and a half weeks given we have 2 bank holidays) to get the refund.
After years of happy custom, the end feels a bit two fingers up at me. PN really don't have the same cash flow margins that a lot of their customers have, so taking money for service that won't be provided then hanging on to that for the best part of 2 months after service ends is a bit sour.
Surely if they treated customers fairly at the end they'd be more likely to return? I'd love to come back when they do offer FTTC (assuming they do at some point) but I'd always have this in the back of my mind now.