sounds like a standard trip to most mechanics. the 56 dollars he charged you wasn't enough for the guy.

did removing the heat shields solve the rattling problem?

if you hit bumps and it still rattles. it could be your struts. but from what i know, they should be good for another 20-30k miles. Stock struts should last for quite some time.

take a look at the strut and see if it does look like its leaking oil. let us know what happens.