Chevrolet Repair: Dash Lights, oxygen sensor, dash lights

Question
Curtis, a mechanic did some work on my 19996 Cavalier he changed what he said was a bad starter (I never had trouble with it before he said it was bad) also the engine light on (WHICH IS WHY I BROUGHT IT in) he changed the oxygen sensor and re-programmed the factory installed security system (I do not not have the "clicker" for the door locks).  Now I really don't know what's going on, I  stopped at the store then when I tried to start the car it would kick over and then stop the  "security system" light would come on.  I disconnected the battery several times for different lengths of time NO Good.  Then after about 1 1/2 hours it just started.  In driving it home every idiot light was flashing, the running lights were flashing, the tach was jumping all over.  Now the 'Battery light' is the only light on, what is this light trying to tell me--Bad battery, alt or what?  Please any help.  Just a side note I had my car in to this mechanic 3X(s) for the original problem of the engine light on and he would fix it for about 10 miles then it would come back on.  That was the only light that didn't come on in the last episode.

Thanx

Doug

Answer
Honestly in MY opinion(don't take my word for it) I would take it to a different mechanic and get it fixed, then I would turn around and sue the heck out of the guy for bad work. WOW, sorry but with all that going on I really don't know what to tell you without looking at it. I don't even know where to start.