All purchases can only be disputed through Facebook. Supercity does not handle payments, they are all handled through the Facebook payment system.
Please go to your Facebook Settings → Payments → Payment History, choose the payment from the list and click on it. You should get a window like the one below:
Click "Get Support" this will connect you with Facebook Support
Please make sure to mention that you would like a refund for the associated charges.
You now have 2 options to contact their support team. live chat and email.
Option 1 live chat: Click on get started and follow the instructions as indicated to you.
option 2: Email make sure to fill out the form fully.