I’m building a review platform

The rule: no receipt, no review. Every review must be backed by a verified purchase receipt, so a fake 1-star from someone who was never a customer can't exist. I filed the patent myself (pro se, 20 claims) and the site is live at proofix.ai — free for businesses while I roll it out locally in Florida. This week I'm emailing 20 local shops a day. Still zero signed up. If you've done cold outreach to local businesses, what actually got you replies?