Villa Marina Union 76 Gas Station tried to overcharge my son for auto repair. Marina del REy, California

My son, who is 20,  called AAA on 3/31 to have his car towed to his mechanic in Venice.  My son thought he had a broken water hose.  Through AAA, ,Union 76 sent a truck to tow him; the driver told my son since he was a valued member of AAA, he could get a better deal with Union 76 mechanics. He agreed.  The driver brought him to Union 76, and my son told him that he thought it was simply a broken hose.  They asked him to sign a sheet, with a price for $45, and told him it would take about 30 minutes.  My son thought they meant to fix the car. After 30 minutes, they informed him it would be at least $500, with probably more stuff to be fixed.  My son was confused because he thought he was paying $45 for a new hose.  My son called me, and I called AAA. They were very helpful and called the 76 Station to take my son to his original mechanic.  the 76 Station would NOT let my son leave without paying $43.  Nothing was fixed.  I called Union 76, talked with Kevin, and got the runaround...they need to charge an assessment fee before looking at the car; he took no responsbility for the driver, indicating that he wasn't en employee.  This was an obvious ploy to charge my son whatever they could .  My son took his car to his mechanic in Venice, who assessed the cost to be $300.  Kevin refused to give my son back his money.  Union 76 tried to charge my son more than $540, an overcharge of about $240.  No one should have to go through this abuse.