Users report multiple fails to submit form

Question

My test-user base (actually, they were not intended to be testers...) reports that they can't tell when the form has been submitted.
They sometimes are on Macs, some are using Chrome browser, others can't open the form at all (could they have been on iPads?).
The form was created in Word, saved as a PDF, form fields added in Acrobat XI Pro, and then uploaded to FormsCentral. I deliver the form via a link to the pdf on my webspace.
Some users are not having a problem. Those who are clever enough to save their form and then email it to me can have the form uploaded from my system; they then receive their own submission response email (it uses their email from the form field).
Most of those who are successful do not report satisfaction with the small size of the alert box that tells them it has been uploaded (or just don't see it); there is an alert box that appears before the aforementioned alert that is confusing people as well. Is this a pop-up that might be blocked?
This is a very game bunch, and they are willing to fill in the form, print it, and hand it to me (oh, boy), so I will get the data any which way, but it would be better to come via FormsCentral.
Any enlightening comments here?

Answer 1

Thanks, Randy,
That had not occurred to me. I have not used a Mac for years! And although I love Chrome, it seems to have "gone west" from my computer and will no longer load.
I was not able to raise the initial dialog, but here is the successful submission dialog:
Is there any way to style the text, or at least make it larger?
By the way, I am enjoying getting to know FormsCentral. I see that although I can use Adobe Reader on my Kindle (and presumably my Motorola, which is also Android), they do not support forms, either.
Beth