I died in the frontier with my friend last night and he picked up al of my items and then re turned them to me i then/home and disconnected for the night, i just got on and im still at my base but i have no items in my inventory quick help would be appreciated thank you.
All I can think of is you used /home outside of the protected outpost and died before you logged out or after you logged in without noticing. I believe if you try /dlog in game it will tell you your recent deaths so you can find this out for yourself. If this is just some really bad glitch or bug though I'm not sure.
Some things... /home only works in town or in protected areas (such as the outposts) but not in the Frontier itself, it's all vanilla based. So is it possible that you used /home assuming to get teleported while you didn't? /dlog (short for "/deathlog") as suggested by Kami can definitely help here. That might shed some more light on what happened to you (and where).
You died on a different server (SMP7) to the one you reconnected on (SMP3). Type /smp7 to go back to that one next time you're on If you want to move the items to SMP3, you can type /vault to open a cross-server inventory which lets you move items to another SMP