I think both are the same, I guess it is an official mirror site of minebit.com  because I can login to minebit.io as well.
About your withdrawal,  if  it is not appeared in your transaction list means that it is not processed yet but based on my own experience, all my withdrawals were processed fast/instant.
Except the one which was cancelled because they needed to verify my winning bet with the provider.
Have you just won a big amount of money here? Something more than $1k seems to be a big amount to be reviewed here based on my own experience so if your withdrawal amount is big enough then it might be the reason why your withdrawal is still not available in the transaction list until it is processed or cancelled.