A toll-free phone number for your Shopify store gives you credibility and signals your customers you’re serious.
From the Schneier on Security blog
This is a newly unclassified NSA history of its reaction to academic cryptography in the 1970s: “NSA Comes Out of the Closet: The Debate over Public Cryptography in the Inman Era,” Cryptographic Quarterly, Spring 1996, author still classified.