Thank you for reaching out to us. I understand the desire for discretion, especially when not working with a traditional brick-and-mortar setup or nonprofit. That said, it is part of our Terms and Conditions (Section 5.1, B - Messages) so that we and all our customers can be compliant with various anti-spam laws both foreign and domestic. For this reason a physical address or US PO Box is required to utilize our services.
For more information on the CAN-SPAM Act, feel free to read our article on the subject and how it affects you.
If you have any additional questions or concerns, feel free to reply to this thread or create a new one, and we'd be happy to assist.