There is a native integration with Teamleader Focus but it only syncs Contacts so that wouldn't help much here. I was able to find this online that may help (with Zapier).
Otherwise I believe the solution will be to use the HubSpot import tool, with it you can associate two objects together, you can find more information below:
Hi @Kirekchiev , as @TiphaineCuisset suggested, IMO the best way to handle your existing ticket data will be via import.
This will allow you to export your data from Teamleader and modify as needed to fit any custom properties you'll use in HubSpot before importing.
The Zapier looks like it is designed to work the other way, from HubSpot to Teamleader and I didn't see an option for ticket creation in HubSpot.
A couple of suggestions:
1 - run a test import using a smaller export from Teamleader, maybe do 1 month of your oldest tickets and do a smaller test with open tickets.
2 - wait to import your open tickets until your team is ready to start working in HubSpot, importing changes will cause a lot of rework. Use your old tickets to fine-tune the import process and use batches to optimize your data accordingly.
I found how to import the tickets but I stumbled upon another issue.
How do I import the emails(ticket replies) from TeamLeader to Hubspot.
The initial message here is the description of the ticket and every follow-up message is email. How do I make sure that I will import all the messages from Teamleader?