For purchase queries, please tap on the chat icon button/contact us (top right) or bottom left if you are using a browser.  Then choose the relevant platform followed by 'Purchase Issues Or Refund Requests'.
Please try to provide as much information as possible that is relevant to the purchase, such as a screenshot of the purchase, the purchase reference number etc.  
Please note that for purchases made on iOS devices, you will need to contact Apple directly: Tap here