I purchased a game yesterday, however due to some issue the purchase failed, yet the amount was deducted. I contacted the bank and they registered my complaint and informed me that either I'll receive the money back or the merchant will. Being impatient I purchased the same game later, but my previous transaction was also sent to the merchant, which I found out when I enquired the status of my complaint with the bank. Now I have no idea how to resolve this, I have not received any receipt for the previous transaction as well.
As updated by OP the first payment has been cancelled after verifying in the payments Center
Since the payment had been honoured by the bank prior to the cancellation (likely), you can contact Google and talk to them and request for a refund (or from the Google Play Settings →
Help and feedback)
Typical refund requests time line here
Follow the steps provided by Google support on how to request a refund.
Here's what you got to do:
Open play.google.com/store/account in a browser
Find the app in your purchased list,
Press on the three dots found to the right of the app name.
Press on, report a problem
In the drop down list, pick I purchased this but did not receive it
It will give you an option to describe the issue in full detail.
After filling in as many details, press submit
If however the app doesn't appear in the purchased list, use Google's page for reporting unrecognized charges, as they don't seem to havea double charge page.
Go to this page and fill out the necessary info.