Your case is different since the job requiring your problem is not originally intended for the support work. There’s a warning message on the deposit address once you open the deposit page.

Your best chance is to get the attention of Duelbits representative so that he will find a way to personally follow your case until it's finish. Your case is a bit not top priority since the mistake is from your side and it can be considered as loss already due to the warning message as reminder before you deposit.

You will Just have to be patient, atleast, that is all you can do since I personally see or feel that you don't have much of a choice, duelbits can decide not to help you with the claim that they do not have the private key to the network where you sent your coins to, and there will be absolutely nothing you can do about it.., the mistake is entirely yours and as unfortunate as it may sound, you are completely at the mercy of duelbits right now, they can decide to help you and they can decide not to help you..

So just keep reminding them and be patient, the issue is something they will help you solve at their own convenient time, I will only advise that you take the advise of AbuBhakar and put into consideration., find a duelbits representative who can help you be in charge of the case until it's resolved.