screen says sales are confirmed but not getting payment or emails

I am new to Zen and I am having major problems. When a customer orders a product, they receive a "Thank you" screen like everything is fine. However, I am not receiving a confirmation email or payment. When I am in test mode, everything works. But production mode causes the following error within Zen: "Preview Only ... Current Price Status ... Preview Only". I have seen this answered but I cannot figure out where ZGN is or if this is my issue. My apologies for these questions, but I would like my cart to work properly. Thanks for any help!!

"Preview Only" is not part of any built-in features of the current version of Zen Cart.
So, it sounds like you're running into something caused by an addon you're using.

I was able to fix the 'Preview Only problem'. Here is another issue. I had a customer who purchased a product, received an onscreen "Thank You", but I never received the receipt/confirmation email Nor did I receive payment. How do resolve this issue: do I have them repurchase?

Well, since that's not normal behavior for out-of-the-box Zen Cart, it suggests that your problems are related to addons you've installed, or changes you've made to the software.

Without knowing any of the details of what's unique to your site, we can't really help you specifically.
Need to know which payment module your customers are using when this happens.
Does it happen to all purchases?
What happens when you make a purchase from your own store? Do you encounter the same symptoms?
Plus, we need your answers to all the questions shown in the Posting Tips section of the Reply screen, which appears when you click Reply below. There's a reason why those are presented to you when you make a post ;)