Once a transaction is cancelled/failed, it usually takes 5-7 working days for the amount to reflect back in your account. This is an automated process and the refund will reflect in your account - your credit limit will be increased for the transaction value.
In case its been more than 5-6 working days and you have not received the refund please share the following details and we will check and update you -
1) Transaction ID
3) Date of transaction
4) Screenshot or reference number of refund initiated from merchant (if any)