Previous supplier not been notified?

I just changed over to Bulb, I’ve done my first pre payment top up with the Bulb key, all issue free.
However yesterday I received and email from my previous supplier saying I had been using the wrong key and needed to ensure I used theirs, with instructions on how to set it to the meter again. I was under the impression Bulb did all the switching for me and I didn’t need to tell them I was leaving?!

EDF sent the same email to me . My electric key come last week.My gas card didn’t. Re order another gas card.Still not here. No gas run out for a week.Old EDF gas card doesn’t work.
Meanwhile im running up a debt to who?
Just for reference. I lived China 9 years. None of these problems exist.
No standing Charges.
No accounts.
Meters are tied to property not people. So you pay you get. Don’t pay don’t get. Very simple. No use for 6 months or what ever no charge because no standing charges.
One supplier. Always kept the lowest price possible. No need to talk to anyone.
Got a problem with supply ? Np just pop into any of the suppliers offices which are widespread in every city town. Problems dealt with same day.
Bill once a month to address not me.
Bill is: Electric, Gas, Water, Housing service. On one sheet. Very clear and simple. Go to your local housing office pay the bill. That’s it, done over with in 5 minutes. Average bill 200 rmb month up to 600 rmb when AC on full time in summer.
No other bills.

oh yeah forgot to mention internet. Same day connect. local office. One off payment for year. Optic box in your house. Just plug in. LAN cable .speed @ least 80. for 1000 rmb a year average.

We UK people put up with nonsense because we are forced to
This is why we cant compete.

What happened regarding your electric key then?