My meter used to be in my back yard. The meter people could never get in, because I keep the gate locked (to keep dogs in and prevent accidents). They were calling me and getting upset that they could never read the meter. I asked for a call the day they were coming and I'd leave the gate unlocked for them. They told me they had too many customers to "call each one individually prior to a visit"... whatever. I said the gate was staying locked, what other alternatives do I have? The next week they moved the meter out to the street, and no longer need access.
I would call the company and ask what the alternatives are. Really this is a huge liability to risk it happening again.
Dogs learn to hate people in uniforms pretty easily. Meter reader/mailman/UPS shows up, always looks the same, and every time the dog barks and "scares off" these intruders. The dog feels awesome, he saved the day in his mind! And oh is he ready the next time this "threat" shows up. This builds and builds until it changes from just barking to "I'm gonna do something". Most of the time they haven't had bad experiences, they are just learning that aggression towards this person gets them to go away (which is the goal) and so it escalates until it is truly a problem.
People in this kind of field get hurt and harassed by dogs so much, that they tend to have a short fuse with the dogs.