I just had my 97 Jeep Cherokee serviced and all hell broke loose

Had routine oil change, and AC recharge. During this I was informed of a
transmission leak at transmission seal. Recommended replace transmission
seal and clean engine and underbody to detect any other leaks, return in 3
days and they will check. After this was done and they started up my car the
alternator light came on. They drove it around block, said light went off and
seems okay.....if light comes on come right back. Less then ten miles and
car stalled, alternator light on. Restarted, check engine light came on, made
it to home and noted that transmission struggled and never got out of 2nd,
3rd gear? When I put it in park engine revved. Checked trans fluid, overfilled,
checked oil and was at add point. I had my car towed back to service
station. My questions: Will overfill of trans fluid cause this? Will spraying
chemical gunk all over engine and undercarriage and hosing off with water
cause this?....Subsequently my car was then towed to another mechanic
with fyi it will be 2 days at least and was then to be towed to a transmission
place with fyi it will be at least a week....So I said okay(distraught) both of
these were recommended by original service person because he could not
figure out what was wrong, he promised to keep track and call me as soon
as he found out. Amazing was 1 day later I get a call, your car is done and
back here a ready for pick up! What, the other mechanic fixed it all? It
doesn't need to go to transmission place? No it is all fixed.....What do you
think?