Cannondale Six5, Specialized Stumpjumper FSR & old Hard Rock
Yes, get rid of it. You will save yourself weight, aggrivation & pain. When I got back into riding, I started on a Trek hybrid w/ a suspension seat post. Once I got rid of it, the bike fit me much better & I was less fatigued after my rides. Shortly after I got rid of the hybrid seat, tires, and eventually the whole bike followed. However, that bike got me into cycling, so I'm thankful for that.
too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
The internals of each post are unique to each maker, so your only hope of getting replacement parts is to contact the maker. Ask for both parts of the keyway system that keeps the top and bottom aligned.
If it came on a bike, and the bike isn't too old, you might also contact the bike company and ask about repair or replacement. Odds are you will not get the parts, but you might get a new post free if you ask nicely. Otherwise buy a replacement post with or without suspension as you prefer.
I would also get rid of the suspension post. Aluminum frames are stiff and transmit road irregularities; the bike companies dampen this with suspension posts. You may consider a carbon fiber seat post. They soak up road bumps pretty well compared to aluminum.