Few weeks back, I was having problem with my Lock Cylinder.
Initially, when I inserted the key in the ignition, it was not
spinning.  I applied little force and then it completely stated
spinning.  After couple of tries, I got the the key in 2nd stage, the
stage before car starts, and then again it started spinning and got
locked.  Now the status was that my ignition was locked and car was
stuck in 2nd stage.

I towed to local garage where they fix BMW.  The mechanic told me that
I need to replace Ignition cylinder in order to fix the problem.  Upon
my permission, he replaced it.  Now my car starts; however, ignition
keep spinning if I do not insert the key properly.  When I went back
and talked to the guy, he told me that he only replaced Ignition
Cylinder Housing and now if I want to fix the spinning problem, then I
have to get him actual cylinder that sits in the housing.  I have
feeling that mechanic ripped me off.

My question is:

1.) Is it possible for the ignition to keep spinning if you replace
the housing?
2.) Would spinning creates problem in the future?
3.) If possible, can any one explain me how housing and cylinder that
sits in connects to each other.

P.S. He also made me get the master key in order to fix the problem.

Year: 1997
Model: 328i

Thanks,

AP