The Roblox Trading System is often abused by people with malicious intent for things like draining limited items and Robux from accounts or something similar. Usually, people have to directly contact Roblox Support via email to get proper action taken, and the email isn’t always useful or helpful in resolving issues like this as in my case.
Similar to how a game has the “Report Abuse” button and can click on thumbnails and other content, the trade page should have a report abuse button below any given trade and can flag the trade to moderators to determine if the trade is abusive or malicious in any way. A moderator could look at the trade, any past trades, and come to a good conclusion on whether or not to undo trades, restore items, or to punish users.
Moderators can get context in the form of the messages attached to the report, which the original poster will describe their exact issue. This is not meant for good or bad trades, it’s meant for blatantly bad ones, attached is an example that I found from the DevForums a while back.
If something like this pops up, the moderator could probably understand that something’s not right and players can flag it for review - others trades are visible to the moderator already so they can understand what went on.