Look my friend with no offence, and they would not steel it, you can lose your bagage if you are traveling with Qatar Airways do you think qatar airways will steel your bag? it is always hapening in the airports
I have been working in Qatar for the last 25 years and since then I'm using DHL.
I don't think this is really what have happened.
there lots of reasons to lose your mobile, but I'm sure if you have bought insurance you will fully compensate.

it is safe to pay a car from nasser bin khaled, but would you drive it without insurance ?

face it man, it is not DHL to be blamed I guess it is just a bad luck when you tried to save some money