unread e-mail ack and followup

Experts,

I am having a dilemma here, hope 'can get some clarifications here.

A little background:

1. Sent a 6-slide pres on value-prop and differentiators of our solution in the very first e-mail to a C-level exec of a big-corp. Got "read" ack.

2. Send e-mail after 3-days, asking for a meeting ; Got "read" ack.

3. Meanwhile have been calling and getting stuck with gatekeeper, his admin; asked her if she can find me a slot for 30mts meeting, she said she would, but hadnt so far

4. Yesterday, I sent a news article about an event that had occurred in a different corp leading to monetary loss (just to point out the problem we can solve with our solution) --> "Not read" ack from the exec. [it means, he has deleted without reading]

My Q: does #4 indicate any sense of "back-off" or is it merely that "I know the issues, and dont need to read such e-mails" from the exec?

The admin is friendly, but so far no apptmt with that big-wig.

Any ideas.. Thx

PS: before someone asks, I always utilize "ack" feature of e-mails. -novicesales