They probably won't call. Was your experience letter on a company's letter head that has the email address & phone number?
(Consider helping them find your company online. Add your company's name & address to Google maps/community... i did something similar back then, can't remember now (
@ishq74 did something more detailed & can ecplain better).
Do this:
Resend the experience letter with a letter for explanation that your GCMS notes show a a RR for bla bla but that your company is a legitimate company despite having very little online presence & they can email or call the company to get that confirmed..