Invasion of privacy

Last week we had our lockers and personal belongongs searched for missing stock, without being asked if we could submit to a search. During this search, one of my zips on my rucksack may have been snagged, I'm not accusing them of doing it, It may have been done by me in the past but I don't know. I have sent an e-mail to head off my HR dept asking them to investigate it, they have not responded to it yet, I personally think that they know they are in the wrong here and don't want to reply to me. In my contract and it states: you will be required to agree to a personal search and/or a search of your baggage, personal items, lockers and car etc, when requested to do so by an authorised security officer/ designated manager. If you unreasonably refuse to submit a search in accordance with this rule you may be subject to disciplinary action.
Now we didn't even have a chance to refuse, not that I would've anyway as I have nothing to hide, but its the principal of the matter, we weren't asked to submit to a search.
Do I have a case here, damages to my rucksack, invasion of privacy and for them breaking the rules of my contract??????

They normally must have permission to search your personal items, purses, personal effects bags etc.

You could consult your nearest Department of Labor office to briefly discuss the issue with them first...you may also want to ask the company to put what is happening in writing and explain to them that you may have attorneys review the situation...try speaking to a higher level of management about the issue; they may override the other managers. If none of these efforts resolves the issue, let us know.