But the question is: did you win anything or are you down at 1xbit? Probably if you are giving them money they are really kind to you. Once you start winning they will not be that kind anymore...
1xbit has been paying me money (in Bitcoin) regularly for several months. Transfers are always on time, so I have a good opinion about this service. Personally, they never gave me a reason to change my mind.
so ask your friend to create an account on this site and make a deposit and then bet on that site for months to test if they won't block your friend when your friend wins a lot. try this and see for yourself that they are scammers.
At the moment I play with small amounts and have not had any problems at all.
If I had even provided evidence that I had withdrawn large sums, would you believe that it correct? I'm sure I would have been accused straight away that it was fixed with 1xbit to prove that they are honest.
And have you been cheated somehow by 1xbit that you accusing them?