i am trying to make sense of this. JGL's character isn't from the future at all, he's in "our present", so do the mobsters of the future come back and approach people for these Looper hitmen positions?
wouldn't killing his future self result in sort of a constant loop of future selves? since in his present he is still alive and able to age in their future?
Having not seen the film, I can only answer your inquiries based on the teaser trailer and plot synopsis.
Joseph Gordon-Levitt's character works for a company that has access to time travel in the future (thirty years ahead of the present in the film). They send targets to a specific location back to the present (the protagonist's time) and they're killed and disposed of by the Loopers.
A constant loop? I don't believe so. Killing his future self would just complete the hypothetical "circle" of life. He'd age to that particular point and time, then die by his own hand.
I'd imagine the inner-workings of the organization, precisely how time travel plays a role in this setting, and why his character was sent back to be murdered will be plot points revealed as the film's narrative unfolds.