I have the same issue and have been using their service since 2013 and never have had any problems until now.
Thanks for writing on the forum. I expected bit-miner.com had some long-term happy customers and am glad to hear that things worked normally in the past and that I am not the only customer having a problem with withdrawals.
Have my email hosted as an g-suite account and can confirm from their logs that no email ever reaches google;s servers
(Was thinking of emails where being blocked since it always had worked before)
My email is on a small ISP, and initially, I also thought maybe their mail was blocked as spam but my logs also show no mail to confirm the withdrawal ever arrives from their email robot.
The last time the email robot worked correctly for me was Feb 01 2018.
I also have no new information since I started reporting the problem on ~14 Feb 2018 and no email replies from support.