How do I get a refund for my Skype Credit?

Unused Skype Credit cannot be refunded.

You can still use your credit to make phone calls from the Skype Dial Pad page on the Web:

https://calling.web.skype.com

You can only get a refund for Skype Credit if it’s unused and bought within the last 14 days. Go to your Skype account, check your purchase history, and if you're eligible, there should be a refund option there. If it’s past 14 days, refunds usually aren’t possible.