Hi there, info22.
Thanks for posting in the Community. I'm here to get you pointed in the right direction for syncing Housecall Pro with QuickBooks Online.
Since the data you sync is coming from a third party app, I recommend you contact Housecall Customer Support Specialists. This team will be able to assist you further with importing the information coming from their system.
You can call them directly from the link attached below (scroll down to Frequently asked questions):
https://apps.intuit.com/app/apps/appdetails?shortName=housecall-pro&locale=en-us
If you need assistance from me, I'm just a reply away. You have a great day.