A $100 deduction seems a little steep for a recording. The fee usually paid to an abstractor to perform a recording and update of title is usually only $50 in this area. It may be even less in your area. This is an expense that the client would have incurred no matter which abstractor to which they assigned the recording, and should not be charged back to you.What expenses could they possibly have had other than the cost of overnighting the recording to another abstractor?
Isn't it usually customary for a client to call an abstractor to find out if they are available to perform a recording before overnighting the documents in order to avoid precisely the problem that has resulted here?

In effect the client is either passing along an expense to you or charging you a penalty. Either way you are being billed. As such you have a right to know exactly what it is for which you are being billed. You have the legal right to an itemized break down of each expense for which the client is charging you. You should demand a detailed accounting. If they are unable to justify the deduction, you may have a reasonable basis for a civil action for contract breach or possibly a suit sounding in tort for conversion of funds. Your state's law may even provide for additional remedies.

You may also want to check with your local law enforcement authorities to see if the facts surrounding the deduction would constitute theft of services under the law of your state.