Here's a potential post:

Hi, I'm reaching out to seek assistance with a concerning issue I've encountered with a product listing on my Amazon store. I own a brand (that I have sold for a while) and have recently discovered that a third-party seller has changed the product title to include their brand name, which is not authorised by me.

The issue is that when I try to update the product title to reflect the correct information, Amazon's system is preventing me from making the change. It appears that Amazon is flagging the title as "protected" because it contains the brand name that was added by the seller. As a result, I'm unable to update the title to reflect my ownership of the brand.

I would appreciate it if someone could assist me in resolving this issue.

Thank you