Don't do business with B2BMach4.
They claim that they can advertise your business 500,000 prospective email clients. The truth of the matter is that none of those people will actually want to read their spam mails and you'll end up loosing a lot of mail.
They also don't re-act to spam unsubscribe requests and have been listed on ISPA's Hall of shame for spam: http://ispa.org.za/spam/hall-of-shame/#2539
Please block all mails from b2bmach4.info on you spam filters.
ISP's around the globe spend millions every year on spam prevention, either directly or through wasted internet bandwidth and cost associated with more powerful servers and networks to cope with the high demand of unsolicited email that pass through their networks. The ISP's, in turn pass those costs on to the companies using their networks, who generally pass the cost on the end user and clients. So this affects us all.