I stopped using Super Shuttle after the second time they didn't show up to pick me up at the appointed time. The last time I flew, I booked a local taxi to pick me up. It cost about $10 more than Super Shuttle but was worth it.
Super Shuttle did refund my fare and paid the parking fee I incurred when I had to drive to the airport--it was too late to find an Uber, Lyft, or taxi if I wanted to make my flight--but they never explained why the driver didn't show up, nor did they apologize. I think they didn't have other passengers in my area and just decided not to send anybody to pick me up. They could have at least notified me, though, so I could have made other arrangements instead of scrambling around at the last minute.
I'm not surprised they are going out of business after reading the Yelp reviews in my area.