I had exactly the same thing happen to my van.The shop that I was parked outside of when it happened was very helpful.
I asked them if they saw anyone hit my van. They told me they heard a loud crunch when the fruit and veg delivery driver went past my van.
.......so after some phone calls, I convinced the business owner to pay up.
My glass was not smashed, but the rest had to be replaced. It cost me just over $300 for the parts from Burwin's. Took me an hour to replace it myself.
The only fiddley bit was that all the antennas are located in that mirror.
John