According to Baka Updates (which I don't know if is a reliable source) There are seven volumes - complete - in the country of origin (ie; Japan) but the last known scan is from 900 days ago and it has not been fully scanlated. So this has likely been dropped. The group doing the scanning is still active though.
I did not check them out, but this link says there are raws available for chapters 4-5 http://zerosum-comics.livejournal.com/14373.html
if anyone can read Japanese you can buy all the books here ( http://www.ebay.co.uk/itm/000000-ultra-black-1-7-Comic-Complete-set-Japanese-Manga-Book-/190987944745?pt=US_Comics_Manga&hash=item2c77c4c329 ) and if your really nice you could translate it for us all that are dieing fot the updates ☆*・゜゚・*(^O^)/*・゜゚・*☆
the only way to buy the actual books in english is for a group/company to license it. for this series it is very unlikely that a company will license it, considering has already been finished. so the only thing to do now is wait and see if a scanlation group will want to translate this series anymore.
personally, i hope someone will take this series under their wing. (/TДT)/
Has this manga been dropped!!!!????? T T