How do I post a complaint about someone cancelling an hour after drop off was supposed to happen?

We had set up drop off at 9am, we arrived to the house with no confirmation because the sitter did NOT respond to text messages even though he had sent us his number just the day before. Then, who opened the door said they had no idea who the sitter was and that it was the wrong address. Then the sitter did not pick up calls, respond on rover or text message. He just sent a cancellation an hour later, no explanation, apology or plan B. We had to look for a backup in a few hours, ended up like $70 more than expected and Rover was just like Here! Have a $20 discount for next time! Absolutely awful and messed up our plans.