eBay is extremely particular about what to list and what not to list.
Being a global online retail website, not only does it have to maintain the local legal restrictions, but also have to maintain its own buyers and sellers safety and security.
They will remove listings from, from your eBay store, if they find it to be in violation of their rules.
NOTE: eBay will send out an email to the eBay store owner and notify them about the reason for removal.
A few out of the many reasons why the listings on eBay might have had been removed, are below:
Most commonly, the listing might've had violated any of their prohibitions or their restrictions
The listing contained material that infringed others business owners rights. This means that listing might be using someone's copyrighted material.
Could be a duplicate listing in your store or between your store or might have to revise the listing to meet the eBay standards. Sometimes eBay store owners, owning 2 or more eBay stores will post the same item on both their stores with the same details. Well eBay will remove one of them when they find out that its a duplicate.