Tried this and it worked for me. Maybe it will work for you also. Keep in mind that just because this worked for me does not mean it will work for everyone. Try it and if it doesn’t work try switching channels also. If neither work then it may require you to wait until IMC does a patch or something.
I listed all my MP items in Klai, was just in Orsha to start on some Orsha quests and looked on the MP and all my items were in the “sell” tab safe and sound on the Orsha MP NPC.
So if you are missing items and listed them in Klai, try looking at the MP in Orsha instead (you can buy a warp scroll to orsha at the item vendor for 500 silver)
If you listed your items in Orsha, then try looking at the MP NPC in Klai instead (if the items you listed in Orsha disappeared like the ones I listed in Klai did).
Still not seeing your stuff? Try swapping channels too. When I was able to see my items on the Orsha MP I was in channel 13. So try that channel if you aren’t already in it. If you are already in channel 13 and don’t see your stuff then try a different channel. If you still aren’t seeing anything after trying the different city AND different channel, then you probably have to wait for a fix (i’m sorry :()
Hope that helps some people get back valuable items they had listed.