Update on Jan 25 2019
I requested a partial refund since the miner performs 20% lower than it should, but Innosilicon declined.
Innosilicon only offered me return for exchange, but I would have to pay for shipping. By the time I would receive the new device - in hope it is not another a lemon miner - I would have at least one month loss from not mining plus in the meantime the difficulty would have been increased.
To sum it up: I would have to spend a few hundred Dollar for shipping, I would have the loss for min 1 months not mining plus lower profits due to an increased difficulty when the new miner arrives - this is not helpful, because I would be loosing out big time.
It is not worth the wait and the extra money I'd have to spend.
Lousy customer service Innosilicon!