Issues with Email Sequencer Personalization and Feedback Visibility

I'm trying to use the email sequencer. Based on a few email responses I've received, the personalization like {{Company Name}} or {{First Name}} are being sent without actually being personalized. There appears to be no way to verify what is being sent out or whether this is happening. How can I adjust if there is no visibility or feedback until it is negative feedback after 1, 10, 100, or 1000 sends?