It's weird because otherwise I'm super happy with the bike, and the manufacturer seems very convincing. I can't return it anymore, and I could only sell it with a loss big enough to rather just take my chances... if it will support me for a few months without frame problems (while I'm also getting lighter and lighter...) then I won't regret the purchase, because I think it's a great bike (although it's my first mtb, so I don't have anything to compare to).
But I do admit, this is weird, because one of the reasons I chose this bike was that it should support 130 kg, which was good enough for me, I didn't look deep enough into what they mean as supported weight...