You have to be more specific here. The 3+ hour delay could be caused by Nitrogensports,
because they haven´t processed your withdrawal at all. But is is entirely possible that they already
processed the withdrawal and you are waiting due to a filled mempool of the BTC network.

I assume that you have received the withdrawal in the meantime, otherwise you could try using
one of these transaction accelerators if you are waiting for confirmations. If Nitrogensports is responsible
that of course won´t help.