Hi, Draden.
For getting a list of phone numbers for Customers, using the PhoneNumber DBObject would be a safe bet. The methods get() and get_customer_phone_numbers() should do what you want.
Documentation: https://docs.q2developer.com/api_references/q2_sdk/db/db_objects/phone_number.html?highlight=phone#module-q2_sdk.hq.db.phone_number