Finding Reliable IT Service Providers Using Zendesk: Best Methods and Tools

Hi there-- I am looking for the best method of finding IT service providers that use Zendesk. One way is to pull a list of companies using Clay or Apollo, and then enrich with a BuiltWith integration searching for Zendesk. However, I have heard BuiltWith isn't the best for this-- that it is more accurate searching for tech that is customer facing (CMS, website tech, etc.). Is this true? Not sure if Zendesk counts as customer facing... If I don't go with BuiltWith, what are other scraping options? Zenrows, Claygent? Any thoughts on how to go about this? Thank you!