Afficient Towing Overcharged and towed from an area without signage. Rip Off! Phoenix, Arizona

On March 24, 2010 I was towed by Afficient Towing & Recovery from the Firestone Tire Company in Scottsdale, Arizona.  Not only did they tow me without clear notice (no signs posted in the area I was parked), they also ripped me off and charged me twice the legal amount ($150).  When I went to retrieve my car, I was charged double by John, who said it was after hours and towing fees are double.  I paid the fee and got my car but was upset and wanted to clarify with Scottsdale Police.  They told me this was a recurring scam by towing companies and that they would make a report and dispatch an officer. 
 
I drove back to the tow yard and they said it was legal.  I called Scottsdale Police on speakerphone and the woman confirmed that they were not allowed to charge more than $75 in 24 hours.  The towing company woman refunded me the difference but would not refund the initial $75 for towing my car even though I was parked in an area without signs or notice of no parking. 
 
 
The sign on another part of the parking lot reads VEHICLE TOWED AT VIOLATORS EXPENSE NOT TO EXCEED $75/24 HRS IF YOUR CAR HAS BEEN TOWED. CITY ORDINANCE 2242. 
 
John said that Normal business hours are 9-4:30pm and it is $75 between these hours.  Our owner had a meeting last week with us and said no exceptions, anyone after 4:30pm must be charged double.  Surely a city tow truck company operating out of Tempe, Glendale and Scottsdale should know the law and not take advantage of it.  
 
Not only was I taken advantage of by being over-charged, I was initially parked in a space and surrounded by spaces that have no signage indicating no parking.