If you got the promo with the wrong dates earlier, by now, you should ALSO have gotten this:
Dear avast! user,
on Monday, we sent you an email offering a discounted renewal of your current avast! product.
However, due to an error in our email system setup, it was sent to you too soon. Please accept our sincere apology for this issue, as we have made sure that it will not happen again.
You will receive an email offering the same level of discount for your product 30 days before your license expires, so there´s no need to worry – there will still be a discount for you, even if you decide to renew later.
Please accept our apologies for any inconvenience this may have caused you.
Your avast! team
Thanks, Avast! It's nice to know there are still people who care to make things right when something goes wrong.