If there is no money in the Available section of your Payment Summary eBay use your back up method which is usually your bank account.
However, I see you are a new seller. Have you correctly and fully registered for eBay's Managed Payments? If not, this could be causing the issue.
See here:
You need to provide eBay with details of a bank account and have this account verified. The usual method here, is for eBay to send 2 micro deposits into that nominated bank account for you to receive, and confirm to eBay.
Once this is completed, you will be able to list items for sale, and receive payouts from those sales.
This will show you how to register for eBay's Managed Payments.
https://www.ebay.co.uk/help/help/selling/getting-paid/introducing-managed-payments-ebay?id=4795
If there is an issue with the registration contact eBay Customer Services, who have full access to your account, and can see where the issue lies and explain the steps you now need to take. Or, if there is still an issue refunding.
Contact them this way.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open between 8 a.m. to 10 p.m. on weekdays.
9 a.m. to 6 p.m. on weekends.
I recommend contacting CS very first thing in the morning, when the lines first open, as there's more chance of Dublin answering.
@discountmartuk