ClassiPress is properly responsive, but if you're experiencing issues it would be helpful to get an idea of how it's not looking right for you. A screenshot would be great if you wanted to share this.
We are happy to accept pre-sales questions either here in the forums (as you will have noticed, the pre-sales section does not require registration) or
via email, however all support for our themes is carried out within the forums. This is not to "force" people to do anything, however it allows us to provide support to those who have legitimately purchased our themes. Thanks.