It depends on the City you purchased the device. I was charged the same and discussed this with the a number of employees and even the Apple Consultant who seemed clueless as he butted in and stated it was 18%.
For the most part it should be 9% with the exception of three cities in LA County. If you would like to verify your particular Sale Tax rate you can do so via the following link.
http://www.boe.ca.gov/cgi-bin/rates.cgi?LETTER=L&LIST=COUNTY
I started a thread on the BB forum and someone stated there is a CA e-recycling or eWaste fee. I don't believe there is one as it didn't show up as an item on the register when they were processing the activation and it is no where on the receipt. Even so it would only be $3 and should show up as a separate line item which as it is excluded from Sales Tax collection.
Now as far as who to complain to...I took this with a few people in store and ended with the Mobile area manager who tried his best to help rectify the situation. While he agreed it didn't look right he was only able to provide a partial adjustment. One of the other store associates who was trying to help suggested that I take this to the BBB rather then corporate or in addition to as this could affect a large number of customers.