After waiting around 2 months without any updates, I contacted Hhampuz in this forum. He helped me a lot, he talked with his guys at duelbits and came to the conclusion that they can retrieve the funds at some point in the future so they have credited me with the lost amount. I received it today and I withdrew it successfully, and they don't charge me any fees. Below is the proof they credited the lost amount which is $2418.9 to my duelbits account.
I am really happy for you as you get your amount back. I know how it feels that your money is stuck somewhere for such a long time.
Also, it is good news that campaign managers have good relationships with the gambling sites for which they manage their signatures campaigns and with the help of them, the case get resolved.