I email them asking for what steps/procedure I need to follow and the respond was the link that I provide on my last respond, select the 1st option. In it, there is a comment box and you type out the detail. What I provided was the original ticket info (PNR, routing, flight numbers, ticket number -- just to be safe) and then the ticket info (same PNR, routing, flight numbers, ticket number) that I had completed/travelled already. They refund whatever amount that I am entitle to.
Thank you very much for this explanation.