This allows the customer to pay the service charge based on their experience upon receiving the product and after they bargain and agree with the seller.

Opencart 2.0.0.0, 2.0.1.0, 2.0.1.1, 2.0.2.0, 2.0.3.1, 2.1.0.1, 2.1.0.2, 2.2.0.0, 2.3.0.0, 2.3.0.1, 2.3.0.2 compatibility
This allows the customer to pay the charge based on their experience upon receiving the product and after they bargain and agree with the seller.
OCmod Compatibility.
You can select the product that you want to set as service charge from your admin panel.
You can add as much service charge product as you want.
You can check/review the usage of the module in detail from the demo.