I think you guys are right, I ought to return it, and get a NEW tank instead. And they should be paying for the return. Their customer service just replied. I can send it back to them, their technicians will fix the broken parts, and IF they find a manufacturing defect during the inspection process, my
postage fees for this will be reimbursed at a mitigated amount.
My complaint is about transport damage, not manufacturing defects..
I took the top of yesterday, and I can't get the freaking thing to snap back in place. I can lift the top off, without pulling the lever that's supposed to "unlock" the top. I've tried wiggling it, pressing down on it (it's as if it doesn't go deep enough, so the locking pins can't get a grip), but noting seems to work. I hope you guys understand what I'm trying to explain :-) So maybe some of the locking mechanism also got damaged, or maybe I'm an idiot 
I'll try once again to upload some images.
I'll write to them that I expect them to send me a new tank, I wont be satisfied with them repairing it, because there could be damage that's not visible at the moment, but might cause trouble later on.
I work at hospital, in the department where we receive all the goods (not sure what it's called in English), and I've seen many examples of how the parcel couriers handle the packages (not with care). So of course I knew there was a great risk of transport damage, but on the other hand I expected it to be packed up really good (which I think it was), and labeled with a fragile/handle with care label (no such label). The box was in a box, that was in a box, there could have been some more filling in there to prevent the box from moving around in the box........that was a lot of boxes in one sentence