As others have suggested, ask to speak to a supervisor and request an explanation of the 20% haircut on the settlement. If there are no liens to satisfy, it's likely a tax issue.
It's possible that they are taking the position that you are 20% at fault for the accident, some carriers often take aggressive positions on liability regardless of whether there is any evidence to support the position. However, in that instance you would expect the adjuster to articulate that in settlement negotiations, not after a settlement amount has been reached, so I find that scenario to be unlikely.
Let us know what you learn from a supervisor Lynn, and make sure to give 'em all the hell they want plus some.
