Outrageous overbill by Kanter Automotive

But, as long as people are willing to pay then more power to Kanter. They apparently offer a service that's worth that kind of markup to enough customers to stay in business. This is a prime example of knowledge is power. If the OP knew who to send it to he could have eliminated the middle man and saved a decent chunk of change.

Exactly. If you want the easy road, you bring your part to Kanter and they do all the leg work for you and charge you for it.

If you want to save money, you do the research, contact the company that rebuilds the boxes, ship it on your own and pay them for the rebuild and shipping while cutting out the middle man.

This is why I always go online and ask questions no matter how stupid they may seem. There are always people online who have been there and done that and can steer (no pun) you in the right direction.

OP if you ok'd the initial estimate and extra $100 on top of that, then why are you pissed? Just because you saw how much it really cost to fix vs. how much you paid? Hell, they even offered you a refund. If you don't want to do your own work on these things then you must know that you gotta pay to play.