5 times pushing off

forgot a painting in the plane in locker over the seat. The painting was rolled up in a tube.... thought that this should be easy to recover as jetstar personel would find it and bring to a place where I could pick it up. Made a complaint on the website and was notified that someone would contact me within 15 days (!!!?). Well, after a week I called Jetstar and was transferred to 3 different persons. Last person told me I would be contacted within 3 days. No contact ! after another week I called again and same thing happened. After another week I called again and same thing happened. Now, after 4 weeks I called again and this time I was only transferred to another person once, but she then proclaimed I would be contacted within 3 days.
I have asked them what is the problem. They can just check if they have a painting in tube in the place where they keep lost items. If its there its fine, if its not there, then I know.... But this info is apparently not possible to look up for anybody in Jetstar. The customer centre is not there for helping you out, it is there to keep you out - these people are trained to give you a insensible push off, they are not whatsoever interested in trying to comprehend what you are saying....
Well Jetstar - you can keep my painting and no matter what, I will never fly Jetstar again, will and certainly recommend others to fly with other airlines....