[Yosemite Sam]

It kinda looks like you are stuck between a hard rock and a cafe.

As sad as it is, your Cub dealer is probably no more equipped to get that extension off than your local Wal-Mart.

They should have told you, up front, that they could "Try to get it off, but not making any promises" and that you would ultimately be responsible for the labor costs regardless of the outcome.

Without getting angry (in front of anyone) explaining to the owner that you are unhappy with the work performed, the condition of your now modified tiller extension and the cost of this modification, may or may not net you any desirable results and could very well be counter productive in future dealings with this company. It's up to you to weigh the odds and make a decision as to future action on your part. I can tell you that storming in with your "guns blazing" may get your money back today but will undoubtedly cost you dearly later on.

If that extension is still available, I would try to talk the owner out of a new one in loo of moneys already paid. Thus showing him that you are a reasonable individual but at the same time are not to be taken complete advantage of.

Good luck.