Dahua support struggles

Struggling to get support. Brand new XVR not working as it should. Keep on saying it need firmware upgrade, but none of the firmware received from Dahua work. It keep on saying update failed. Very sluggish on network. Tried different networks, none working. Brand new machine keep giving system busy or low on resources message. Problem is you cannot actually speak to anyone at Dahua, technicians forever busy, you have to do via whatsapp. I spend four hours now on whatsapp with them as response is sporadic and slow with no success whatsoever. I thought they would have better support and infra structure, but they are basically the same as cheaper chinese brands like Andowl or Xiaomi