I had exactly the same when I recontracted earlier this year, and a subsequent promise to resend the message also didn't materialise. A day or two later I got the details by post. It emerged that my long-forgotten preference was for post, and it appears that BT staff don't always check, automatically saying that you'll get an email. So it's possible that you'll shortly get the details through your letterbox.
If it does turn out that you have the postal preference you can ask BT to change it to email; you can't have both. I changed mine and got immediate confirmation of two subsequent changes to my package.
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