Actually there is - failure to refund.

In any situations (not only CX), if you think a refund is due and you don't get it, you can dispute and request a chargeback from your credit card company. As a fact - you can give a call to your credit card company and mention it, see what they will say and you will know if this is the right approach. FWIW:

1. How the credit card company or the merchant to respond is up to them. No one knows if the merchant will provide the response or not. Remember - in order to get a successful chargeback, a credit card holder must prove that a credit should be due.

2. Usually the purpose of disputing and requesting a chargeback is create an avenue with the merchant for discussion.

It may be an awful advice in your opinion. But what is more awful, a merchant that fails to respond a refund request, or a credit card holder filing a chargeback?