Hello,
I pushed battery against positive nobs, contact there seems to be weak point of design, however doesn't help. I checked voltage by multi-meter and voltage is there (tight probes on sides of battery nob). What I noticed is that it smells like burned piece of PCB, didn't wanted opened it and check for burned spots on PCB (it is still in warranty). Anyhow already contacted seller and he is trying to solve this, so will see, if they provide fault description will add it here.
Anyway thanks that you tried :),
Peter