If I had to use the recording, I would cover this fact by saying we screen all interested parties to weed out people who aren't serious. If you don't want to look like Santa, try FAT Crushers. The headline contains no benefit. The entire ad is written as if it belongs on a billboard versus being a classified ad. New FAT Crusher.
Amazing product prevents fat from forming.
The rest of it works except there is no guarantee. I would make it more interesting and cut down on redundant statements. I would drop the return address part and the payment method. People already know how to pay for something by mail. They also know if they want the product they will need to leave an address.