OP Here with an update.
I drove over to the storage yard today to check on the situation. My neighbor did pull in his front slide that was really causing an issue with getting in my front door. However, he still has he rear slide extended into my space. It's not really in the way but it still annoys me that he is in my space. In this picture, you can see that his slide is right up against my storage bin in the back of my slot. He actually had to move it a couple of inches to be able to get his slide out.
The office wasn't open when I was there but I did email the manager that the problem was still not resolved.