If they won't stack the 20% promo I'd cancel the order.
I used the 20% Sunex deal previously and other items that say they are eligible show the promo discount in my cart.
They were $64.99 less 20% off (-$13.00) Sunex Holiday promotion = $51.99 yesterday.
Today's lightning deal = $54.99.
Amazon drops the Sunex promo price but gives $10 off instead. I've noticed this on many lightning deals that had promo deals.
Calling deals "Lightening Deal" may sound like it is a bargain but they aren't always the best deal.
Good psychology move by amazon, but I'll pass.
EDIT: In the end I couldn't resist, sigh. $43.00 (after a couple emails) + tax.
More like a wallet lightening deal, IMO, and I really like amazon but think before you buy...
Of course amazon might jack up the price after the lightning deal higher than it was yesterday.