Complaint Review: Aamco Transmissions; LST Investments

I took my recently purchased car to them to have general service purge and change transmission fluid. I had driven the car for 3 days prior on highways and city traffic with no problems. After an hour in that shop I get a call stating there was no trans fluid showing on stick , and codes and they now needed authorization to charge me above standard fee; which I gave . After 2 hours I get another call ; now I need to have the transmission overhauled @ $2300 . I declined and advised them I'd pick up my car up . I then pay $155. and ask the service advisor to show me the trans fluid level. When we get to the car pop the hood and guess what ? there is no dip stick . I ask how did they read and was told they have a gauge( ok I bite) I then proceed to drive away and now my dash board is lit up like a Christmas tree with check engine , electric code etc.. and to make matters worse now the transmission is slipping . I call back the advisor states possibly the codes appeared due to the scanning performed. Next I call the Customer service * must leave a message * My next call is to the State Atty generals office * They will never touch any vehicle I own!