How to make a claim for NETS flashpay double deduction

Recently I pay the french fries using the NETS Flashpay. When I first tap the card, there was no response from the system. The cashier reset and ask me to tap for another 2 times and finally a receipt was printed out. I checked the amount deduction was correct and throw away the receipt. However when i check the transaction history on the NETS Flashpay and discovered that there was a double deduction.

I search the NETS website(https://www.nets.com.sg/support/faqs/faq-nets-flashpay/i-encountered-double-deduction-when-i-exited-the-car-park-how-do-i-proceed-with-the-claims-of-my-nets-flashpay-card) and only can find the similar solution for the double deduction as follow:

I encountered double deduction when I exited the car park. How do I proceed with the claims of my NETS FlashPay Card?

You may perform a printout of your NETS FlashPay Card statement and email a copy to info@nets.com.sg with the following information:

Customer name (as per NRIC): 
Contact (Mobile preferred): 
NETS FlashPay Card No.:
Transaction Date:
Car park Location:

I send the email to NETS and the reply is as follow :

In conclusion, all the retail double deduction will need to seek refund from the merchant directly. In the end i did not get the refund as this is not worth for the time spend and reason out with the merchant.