I've personally used EXMO a few times in the recent past, though only for transactions of up to 0.2 BTC, not ~1 BTC. I too have had an issue with their extremely slow withdraw times, and it really puts you to the edge of your seat, however it all turned out well.

The second time I had to contact support because I started to get paranoid after 4 hours of waiting for the withdraw to be sent out, however their support turned out to be unresponsive and useless.

Would it be possible to cancel the withdraw and maybe withdraw in smaller increments?