If you are having problems issuing a refund to the registrant's credit card, it could be because you do not have enough money in your Stripe account to issue a refund.
Funds used for issuing refunds are stored right in Stripe, not in TeamLinkt.
To check and see if you have enough money in your Stripe account to issue a refund, go to Stripe.com and check your available balance.
NOTE: by default, Stripe does auto-payouts to your bank account that is linked to your Stripe account. We recommend disabling the auto-payouts in Stripe if you are planning to do refunds!