WOW PowerLeveling: Sending a telegram is often faster than sending a PM as not everyone
Leaving a review for a product that does not work for you should only be done if the developer does not respond WOW PowerLeveling to your attempts at contacting him/her.
While writing a review, keep in mind that it may not be the developer's (intentional) fault that the product doesn't work for you.
You can also attempt to send the developer a Private Message (PM) on the forums:
Copy the developer's name from the Product Details Page (as described in IMVU helper's post).
Go to the forums, and use the link at the very bottom of the pages to go to your PM inbox.
On the inbox page, click the button labeled 'New Post'.
Paste the developer's name in the 'Username' field, or use the button to the right of that field to find the developer's name (in case you're not 100% sure about the spelling).
Sending a telegram is often faster than sending a PM as not everyone uses the forums, but it's still a good alternative, especially when your message doesn't fit in one telegram.
Some developers have a website of their own. Those websites generally include at least one way of contacting them.