I just bought sportlines, and monroe oe spectrum struts. I had them put together, and the spring is very loose in the bottom spring seat, and slides around alot. Is this combination compatible?

 

It's a sign from God telling you not to do it. You've got one of the worst possible combinations with terrible autozone monroe shocks and springs that drop way too low to be functional and don't have enough rate to compensate for the drop (you will be on the bumpstops in the rear).
Cut your losses, do a search and buy a proper setup, you will be be much happier.

 

JD AMG is absolutely right! I had to learn that the hard way. I went with an Eibach Pro-Kit and a set of shocks from Advance Auto (might have been Monroe) and did it that way because it was cheap. The car rode and drove HORRIBLY! Hit the rear bumpstops every time I hit the slightest bump and it got to the point that I hated driving the car. Not sure I made it a year on that set-up before I did it the right way and went with Strano spring and Koni SA shocks. Got my car's ride and handling back and I was finally happy. I tried to take the cheap way out and ended up doing it twice and cost me a lot more in the end. BIG lesson learned!

However, to solve your immediate problem, are the rubber spring isolaters still installed at the top of the springs in the rear? That's the only thing I can think that would allow the rear spring to be loose while installed... If you're talking about the front springs being loose, that shouldn't happen at all once the front assembly is put together. It should be tight even before it goes back in the car if it's assembled properly.

 

Hopefully everything is still in good enough shape to be returned, but yes I'll echo everyone here there are a few people here who have had an ok experience with sportlines. That being said if you're married to your sportlines at least get a better shock (bilstein, koni, etc...)

 

I just put strano springs with Koni str.t's. Ride height perfect and drives real well.

 

Should not be rattling..

Try Sam's combo for comfort performance, or koni S/A's on stock springs, which can be low enough.