With transferring in BTC you have two choices, pay the minimum fee (default option) or pay a higher fee. Unless you chose to pay the higher transaction fee for a quicker confirm time YOU WILL be waiting for over a week before the transaction is confirmed however, you will get your BTC. It is stated on the withdrawal page:

"Bitcoin Network is VERY congested (record high)
See here: https://jochen-hoenicke.de/queue/#3m

That means:

Transactions take a very long time (several DAYS) to confirm
Transaction fees are very high for a quick transfer
We have disabled the previous "Normal" (now called "Low") fee option (which was too low for the current state of the network) and introduced an "Economy" fee below the "High" fee to help you better deal with the Bitcoin network ongoing congested state.
We recommend using Ethereum or Litecoin for your Withdrawal"

If you ignored the suggested transfer method and still chose BTC then you will just have to be patient, you will eventually get your BTC just like I did. I no longer make BTC transfers for anything unless I'm on an exchange.