Oh no, am I in an infinite loop?

Just when I thought my ongoing BT Mobile experience was going nicely after a smooth set-up, I get this email from them:

It really seems to be them, and not a spoof:

Three months ago, in July, I switched from Vodafone to BT Mobile, and received not only a keenly-priced SIM-only deal, but two side-benefits: a very nice JBL speaker and a £65 spending voucher. Getting those to me on the dates they were promised all went to plan. I was very pleased. I still am.

But now there is this strange and unexpected email. Are wheels in motion that will set up a duplicate mobile account with duplicate rewards, and an ongoing duplicate direct debit each month for two SIM cards? I hope not!

What's the betting that they have somehow set up another account? It will be a nightmare to shut down - and quite possibly the original account could vanish with it, leaving me without a mobile phone service. Shriek!

Well, what to do?

I was going to respond to that email at once, but perhaps I should just wait and see. Maybe it's all a computer glitch, without consequences, and I'll hear no more. Particularly as the July deal is no longer on offer, and they can't actually send me another speaker because they've all gone. The deal has changed. 

I have of course checked my BT account (and their Rewards website) for anything odd showing up there. There's nothing.

So...it seems OK. But this episode has shaken my faith in BT Mobile at the very start of our acquaintance. Lesson: you can't relax. You need to stay vigilant for silly errors that might cost you money.