Please see the sample below, after choosing your game ID you will be redirected to the services window with the tabs: Convert WP to KP, VIP package, Ragnarok game coupons and VAS. If there are no tabs whatsoever then it is possible that ID was created through Steam. For that you will need to use Steam client to buy time and KP for the game ID in question.
If however, the page refreshes after choosing the WP amount and clicking on Convert button then likely an issue with the browser.
The following is a step by step walkthrough to assist with 'payment error', it is specially made for that but it should cover any other related technical issue.
https://forums.warpp...-how-to-fix-it/
Should the issue persists then please contact WP Payment Department with detail of your account and issue, make sure to describe the steps taken to reach the point where you are unable to add the points.
How to send a ticket guide:
http://forums.warppo...t-system-guide/