Drei:
I would first call Heartland Service and have them check their list of 3rd party servicers that they have had good results with in your area.
So. Ca. is a big area. You need to localize your request a bit more.
Heartland will not pay the travel charge of any mobile servicer, and the servicer may require you to pay up front and get re-embursed by Heartland. Whatever servicer you use for your warranty repairs, you need to get Heartland's approval IN ADVANCE of the repair call. This should be a routine approval.