You can either go the CONTACTS way to get all contact/contacts data from Wix-CRM-Backend, or you can do almost the same by quering the PMD (PrivateMembersData).
Wix-CRM-Backend…
https://www.wix.com/velo/reference/wix-crm-backend
I have had a disscussion about Wix-CRM and PMD here…
Perhaps it may help you gathering some more informations.
…OR HERE…
…OR HERE…
…OR HERE…
somewhere in one of these posts, i talked about PDM and CRM.