To be honest, the system you guy's have in place for TC trading is extraordinarily convoluted. My guess, this stems from the fact that you've taken an environment that isn't suitable (the forums) and implement measures in an attempt to make it so. The result, you have security but at the cost of usability - this isn't typically considered an acceptable solution. Especially, when you are having to ban and further disenfranchise your user-base to allow the system to function. In my humble opinion, your real issue is that you aren't leaning on automation or properly developed functionality to solve this.

Just as an example, I want to outline what the obvious issues are and then propose how you could develop a feature to resolve it.

Issues with TC Sales
1. How do you determine that the TC being sold comes from legitimate means. Or, more specifically, how do you delay the transfer of said TC until you verify the legitimacy of the earnings.

2. Buyer receives the TC but fails to send the USD amount. The TC is then spent/lost and rendered unrecoverable.

3. The seller receives the USD but fails to send the TC. You obviously cannot reverse a USD sale, nor can you force send TC that doesn't exist or is lost spent/lost after-the-fact.

Issues with Current System
1. Seriously lacking in usability: You've made the sale of TC a logistical headache for your user-base. With a dwindling amount of users, you need to take the fact that they are voicing their frustrations surrounding this seriously.

2. Poor visibility: The system is exclusively forum based, I am willing to bet a large percentage of non-compliance comes from users who are approached to buy TC via in-game or Discord. These users are probably not aware of the system you have in-place.

3. General non-compliance: There is nothing in-place to stop an illegitimate seller from refusing to follow your system, getting the USD and then bolting. Although, I admit this is the hardest issue to solve.

Basic Proposal
I believe you need to develop (as in program) a solution for this. Specifically, as a custom feature in the Torishop. This needs to be simple and fast to use.

Step One (Seller):
Verified sellers are placed in a user-group that grants them access to a "TC Sale" mechanism in the Torishop. The seller kicks off all transactions:

- The seller specifies a user and an amount of TC to send. This TC is placed in holding and assigned a unique transaction ID - placed in holding could be as simple as being sent to a third-party account. The seller is unable to recover TC from holding, it is effectively removed from their account. It would require staff intervention to reverse the trade at this point.

Step Two (Buyer):
The buyer receives a confirmation message stating: The seller's name and that they have initiated a trade, including the amount of TC and transaction ID. At this point, the buyer has an assurance they are not being scammed. Issue 3 from above is resolved.

- The buyer is instructed in this confirmation message to now complete their side of the trade by sending the USD amount via PayPal or another suitable medium to the seller.
- The buyer now waits.

Step Three (Seller):
Upon receiving the USD amount, the seller can access a list of their pending transactions in the Torishop:

- The seller will access the transaction specific to this user and mark it as completed.
- At this stage, you could require further verification in the form of an image upload containing a screenshot of the USD transfer.
- At this point, issue 2 is resolved. The buyer will not receive the TC until the final step takes place.
- Both parties now wait for approval.

Step Four (Staff):
In my view, this step isn't strictly necessary if you trust the vetted sellers. But I understand that you want some human (staff) verification to occur to resolve issue 1 - determining the TC came from a legitimate source. Certain staff, whether that's Market Squad, TSA etc. have access to a list of pending transactions in the Torishop:

- The staff member reviews the transaction and verifies the legitimacy of uploaded evidence and TC source. The staff member then marks this as complete.
- At this point, the TC is released from holding to the buyer.

This can be summarised as:


How This Solves Issues with the Current System:
- Usability: Despite my wall of text, this is pretty usable. The buyer does not need to do anything other than send USD. The seller completes only 1 extra step (upload of USD transfer screenshot) when compared to a regular trade. Staff input/time spent is probably (although I'm estimating) on par if not lower, than the current system.

- Poor Visibility: Hard to solve, I'll admit. Messages need to be included in-game, on the forums and on Discord NOT to send USD payment until a confirmation message is received indicating TC is in holding.

- Intentional Non-Compliance: Again, tricky to solve. Increase visibility as much as possible, make it obvious when a user is/isn't a verified seller and continue a clear stance on not supporting trades that occur outwith the official system. If you make it visible enough, even new users won't be duped by non-verified sellers.