Don't they want my business?
Have you been sending literature requests or requests for quote, but the vendors aren't even responding?
Companies CANNOT and WILL NOT respond
unless you provide TRUSTABLE contact
An inquiry from 'email@example.com', although claiming to be potential business, may actually be a phisher digging for information to use in hacking their credit card system, a competitor monitoring their response time, a foreign company trolling for intelligence on how customer inquiries are handled, or a disgruntled former employee digging for dirt. If a business receives an inquiry that lacks serious contact info (your FULL name, company name if applicable or company-based e-mail address, street address, and/or phone number), that business is usually forced to discard the inquiry without even acknowledging having received it.
Thanks for taking the time to try to see the situation from the vendor's perspective.