I used to work in retail and am absolutely appalled at how you were treated. I'm in the UK where things are maybe different, IDK, but I absolutely would complain. I would write them a letter about why their treatment of you was unacceptable and how they have lost a customer, potentially discouraged other customers, and had a serious effect on your wellbeing.

They need to rethink their policies. The correct thing to do would have been to ask to see inside your bags and to do so a) in private, e.g. in the back office, and b) carefully. The fact they mishandled your stuff is just not on. Even if someone has shoplifted, it's STILL not okay to treat them like this!

I'm so sorry you had this experience. I really would urge you to complain and I would copy it to their head office.