Septic fields, am I being ripped off?

First you need to specify what type of field, here in northern cali a standard (trench with gravel and pipe) for a 3 bedroom house 8k + or -, a high mound (Wisconsin mound) cost about double that, are they replacing the tank as well or just the field.
if it is standard system sound way to high. an aerobic or high mound system maybe
BUT some one treats my lady like that they are apologizing or spiting out teeth and they would not be back at my house