I'm very sorry to hear that. We always recommend checking to make sure an email campaign is displaying consistently across multiple email clients and devices before sending the final version to your contacts. Because each email client has different ways of displaying email content, you'll want to not only preview it for desktop and for mobile, but also send yourself a test. Just start by clicking the Preview button in the top right:
Then you can select the Desktop and Mobile buttons. Finally, you'll want to click Send a Test Email:
If you come across an issue within the test version you'll be able to fix it before your contacts receive your email campaign. Hope this helps!
I'm assuming alot from the original post, like the piece looks well in preview mode.
Here's the truth of this situation that you're kind of turning around on the OP.
If she creates it in YOUR editor and reviews it in YOUR preview then YOU should ensure by testing that it works in all the email clients not YOUR customer. If it doesn't, YOU should maintain a list of non-compatible client combinations or fix the bugs in YOUR editor.
When you take away all the creative control that we used to have, YOU then assume all the liability when it doens't view well, not us.