Can't buy a new subscription

me37, good evening.
Basically as Just Shoot Me says, this offer is for new subscribers, with the only exception.
It's an upgrade from a single subscription to All Apps (provided that you've never used All Apps before).
If you try to process by e-mail or HP, you may get an error like a declaration. In that case, you need to consult customer care.
However, since the period has already expired, you can only contact customer care to discuss whether you can respond.

Adobe Help Center

Those Deals are only for New customers. 

Your subscription will be Auto Renewed at the original price, or higher depending on if the subscription price goes up, on the day you originally sign up for it. The only way for that to not happen is for you to manually Cancel your present subscription and then Sign up for a New one.

There is No Adding on to your current subscription. It is Locked in unless you manually cancel it.

Be aware that there is a cancelation fee of 50% of the remaining subscription cost when you cancel early.

The time to cancel it within the last week of your active subscription period.

But I have no idea if as a current customer, even if you don't have an Active subscription, you would qualify for the deal you were offered in that email.