Zipsale does not touch or delete users items unless requested to do so. The issue will be caused by one of the following.
1) The marketplace is disconnected - When the marketplace is removed the column for it is also taken away. Re connecting will make it show again
2) If no items are showing at all it means you have a filter selected. Please click 'Filter' on the task bar and above the orange accept button will be 'Reset filters' click this then accept and all items will show again.
3) you have a space entered into the search bar, please remove this.