點可以投訴航空公司?

Well... Since you have complained by contacting the airlines, have they sent you any reply??? If yes, there should be a reference number of the case on the letter head, and you can contact the airlines customer services again either by phone, letter or e-mail and quote the reference number, they should be able to follow up from there...
Also, if the airlines have told you through the airport about the case and said would contact you last week... They should also have given you some form of contact person and number to contact with... If not, then just send the airlines another letter or give them another phone call regarding to your case... As they will always open a file for any complains so they could then follow up from there...
If you would like to contact 消委會 regarding to the situation... I would suggest you to contact the airlines again first to see how they reply... If it was unacceptable, they contact 1 of the 消委會 office around Hong Kong to present your case, they will then follow up for you with the airlines if not, they will give you some suggests and ideas...

send them a complaint letter lor!

你仲可以投訴負責為有關航空公司提供行李處理服務的代理公司。

由於未知你所乘坐哪間航空公司的服務, 所以未能進一步提供資料。