They generally asked for your cross streets, then looked at the giant street map on the wall to figure out where you were. Not exactly an unsolvable problem.
Edit: and it’s not like they needed turn by turn directions. Just figure out where to go from the cross streets. Oh it’s northwest of Maple and Cyan, 3 streets into the neighborhood. The drivers can get to the crossroads on their own, that’s just local knowledge.
Where I worked we had a bigass map broken out into a grid. If you didn't know where an address was you could pull out a huge book that had the grid sectioned by street/block address (at least where I worked). So for example if someone had 12013 Lemmy Ln. You could look up in the book Lemmy Ln. Block 12000 and find it was on A4. You learned the entire service area pretty damn quick so like 99% of the time you knew where it was off the top of your head.
It was fun as fuck. Like the most fun job I ever had. I wish money wasn't as important cause I would've done that job for the rest of my life.