Whoa...slow down.
First, there are a lot things that can cause an A/C to stop blowing cold and many of them are very inexpensive to fix.
Second, there is no such box as you described.
Third, start with the basics. You can use the climate control system to determine the refrigerant pressure, evaporator temp, and a host of other things so that you have some idea of what is going on(see fourth).
Fourth, search this forum and you will find dozens of other people who have gone through issues with W202 A/C problems and succesfully fixed them.
Fifth, try to be a whole lot more specific when you post here about what the dealer is tellling you. "Box" means nothing. All of these parts have names. Have the dealer give you a written estimate and post here what they said.

Try to find in indy in your neighborhood that you can trust and use as your go-to guy with this car. You need a second opinion on this if you really are looking at $1000+ for the repair.
Good Luck, Dan

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2012 E350 Bluetech