My opinion for the whole issue is that since you said the CSC guy broke your lens, asking you to purchase the new lens, i suggest that you demand a black & white from them stating that they indeed broke your lens due to neligence in servicing and not by verbally. As if you were to complain the case all the way up to the management or even CASE, there is no concrete evidence for you to win the case. Second, i were you, i were demand to see the highest authorize position personnel in house who is a decision maker rather than any supervisor or manager to rectify this issue and immediately, not delaying it for days, delaying it means they have more reason that it is already broken/spoilt the day you send in. Check your servicing slip, what was the job recommended / requested when you send it in.
Hope this helps and you can get a brand new lens as a replacement with the charges of the "cleaning / servicing" not purchasing the lens.
By the way, are you Jim Chan who used to work with Culina?