Hello BoSungJung.

Sorry to hear you don't want to use the plugin after purchase.

Can you please tell me which additional fee you're referring to? Is it the VAT (Value Added Tax) that is being applied to the transaction?

If this is the fee you're referring to, please note that VAT must be collected on digital products sold to consumers within the EU, on certain inter-state US transactions, and in a growing number of other countries. It is charged on top of the sale price of a product, and must be returned to the relevant tax authority i.e. the governing body at the buyer’s location.

Our reseller - Paddle entirely handles VAT for all digital products sold to countries where this is a legal requirement.

If you meant something else, please let me know, as there should be no additional fees other than $59 for the license and the optional VAT (depending on if it applies in your country).

To obtain a refund, you need to log into http://store.tms-plugins.com/ with the credentials you received in your e-mail when you purchased the plugin, then navigate to Purchases/wpDataTables, and if you're still within 15 days from purchase you will see the "Request Refund" button.