yeah, as stated above, mlnet allocates space for all your downloads, so if you have 14Gb's of dl's going on, they already have the space, no matter if you've only d/l'd 2%, or 98%.
As far as not working, what build are you using? 2.5-3 or -4, there was a problem with the -3 where they dont connect to servers, or wont pickup your ID, and you end up with a Low priority... i've been running -4 for a while, and the last 2 weeks continuous without problems... check your servers for connection priority, if they're all Low, then upping to -4 might be in the future for you.
they do have a good FAQ/Forum section on their site.