Refused to honor a written estimate they provided ...

Refused to honor a written estimate they provided to repair a dent. When they wrote the estimate everything was fine, when I came back to have the work done they said the first written estimate was wrong and they would not honor it.
This was always a cash repair so insurance didn t figure into it at any point. Also to be clear, this was not a case of discovering hidden damage. Of course it would be totally reasonable to start working on a car and discover it needed more work, but that wasn t the case here. They just said the price was now ~$300 higher because the first written estimate was wrong.
It takes a lot of time and effort to get estimates, arrange to drop off your car, get a ride home, etc. So if a mistake was made who would you expect to pay for the trouble, the customer or the business who made the error?
I guess you could say this was only an estimate and they re allowed to change it at any time which is what they said. On one hand that s true. On the other hand, do you want to be a customer for a business where you have to wonder if the price is going to change out from under you?