We have been working for Greenlink for 2 years now.  And as far as I know there is only one Greenlink.  They have several rules to their abstracts, for instance they want everything done on there forms (you get counted against you if you don't use their forms), you send your abstract form (ORC form) to one number and any copies to yet another number.  Oh, and by the way, neither of the numbers are 800's.  There scoring is lousy, and you will be expected to stay on the line with them for at least 10 minutes each week to get your scoring.  I don't know about you but that is 10 minutes that I could use to focus on other abstracting work.