Received email about a debt I don't have?

I’ve been sent an e-mail and text saying I didn’t pay my final bill when I left bulb- but I haven’t left bulb. It also says I owe £7 and sends me a link, but when I log in it says I don’t owe anything. I did move to a smart meter, so it might be confusing all of that.

Anyway, anyone else had the same and can anyone give me some idea of what to do? I don’t get to call during the week when the phones are working because I have work.
best of British