TRANSMISSION RIP OFF

MY CAR BROKE DOWN ON THE WAY TO MY BROTHERS HOUSE IN OCEANSIDE AND I WOUND UP GETTING IT TOWED TO AAMCO BECAUSE I THOUGHT THEY WOULD NOT RIP ME OFF. AS IT TURNED OUT THAT WAS LAST WED. AND I DIDN'T HEAR FROM THEM UNTIL TUES. THE FOLLOWING WEEK. THEY QUOTED ME A FINAL PRICE WITHOUT LETTING ME KNOW THAT THEY STARTED WORKING ON THE CAR WITHOUT AUTHORIZATION FROM ME. THEY ONLY EXPLAINED THAT A MERE $41.00 CHARGE WAS WHAT I WAS EXPECTED TO PAY FOR A ROUTINE CHECK UP OF THE TRANSMISSION, BUT IN FACT THE DECIDED TO GO AHEAD WITH THE CHECK UP AND INCLUDE $600 WORTH OF LABOR WITHOUT MY AUTHORIZATION. ALONG WITH HAULING OUT THE OLD TRANSMISSION AND BEGINNING WORK OF OTHER FIXTURES EVEN THOUGH I DID GIVE THEM AUTHORIZATION AT THE END OF THEIR FINAL QUOTE I IMMIDIATELY CALLED THEM BACK WITHIN A 5 MIN PERIOD AND SPECIFICALLY TOLD THEM TO CANCLE ALL OTHER WORK AND ANY ORDERED PARTS AND THAT I WOULD BE MORE THAN WILLING TO PAY THE CANCELLATION FEE THAT WOULD APPLY. BUT AS OF TODAY THEY IGNORED ALL STORE POLICIES AND CONTINUED THE WORK EVEN THOUGH I CAME TO PICK MY CAR UP AS IS AND EVEN BROUGHT ALONG A FLAT BED TO TOW THE CAR. BUT THEY REFUSED TO LET THE CAR GO AND SO NOW MY LAST RESORT IS TO NOT PAY AND SUE FOR OBSCENE CHARGES MADE TO ME.