There are 2 methods of increasing the funds in your Stripe account so that you can refund a customer. Here's the procedure for each.
Increase funds in my Stripe account
Method 1
By adding funds from your bank account to your Stripe account
Note
With this method, you can quickly reimburse your customer without waiting too long, since by transferring funds from your bank account to your Stripe account, the money is immediately available.
Log in to your Stripe account and click on the Balances tab
Select Add to Balance
Enter the amount and click Next
Then Stripe will provide you with the necessary information for the bank transfer from your bank account to your Stripe account:
institution number (3 digits)
transit number (5 digits)
account number (10 digits)
Make a bank transfer from your bank account (RBC, Desjardins, BMO, etc.)
Once the transfer is complete, attach the confirmation of your transfer (PDF or image), confirm and send it to Stripe.
The next day, you should see the funds on their way to your Stripe account, and you'll be able to process your customer's refund.
Method 2
By changing the frequency of payouts from your Stripe account to your bank account
Note
This method is mainly used by merchants who receive regular payouts from Stripe. By changing the automatic daily transfers option to manual transfers, your Stripe account balance will be automatically increased, as no more automatic payouts will be made. So as soon as your Stripe account balance reaches the amount you want to refund to your customer, you'll be able to make the refund.
Log in to your Stripe account and click on the Balances tab
Select Manage payouts
Select Manage payment frequency, then check Manual and Save
As soon as your Stripe account balance has reached the amount to be refunded to your customer, you can make the refund.