It does say under the funding methods that bitcoin is now exclusive for bitcoin deposits only, when you click the check availability. I never noticed that before. I never deposited that way, but was able to withdraw 2500 the first time, but second time I requested, I was was denied the request and was told via email that I could only withdraw 1000, because I didn't deposit that way.
Good luck, I know before it said that bitcoins were limited availability for non bitcoin depositers, no it seems it's gone, may just have to frequently check back, or maybe hop on live chat and ask if it will become available to non bitcoin depositors in the near future.