It's not a problem. Sometimes it takes time to refund. It's happened to me earlier.
Nothing to worry about since you got your confirmation mail as also transaction is cancelled
If you wish to be doubly sure, you can call or chat with Google help from the Google Play Settings →
Help and feedback
Edit: Just stumbled on this from
Google Play Refund help.
If the status shows cancelled it means
If the status is "Cancelled," the order was never charged and so you will not see a credit on your form of payment.
There is also a detailed table for refund timelines. Summary below :
Credit or debit card - 3 to 5 business days
Direct carrier billing (prepaid / pay-as-you-go) - 1 to 30 business days
Direct carrier billing (postpaid / contract) - 1 to 2 monthly statements
Google Play balance (gift card or credit balance or Google wallet - one business day
Online Banking - 1 to 10 business days
PayPal - 3 to 5 business days