It is not clear what you have done or want to do.
You say yourself that you are new to selling, and that means you have to prove you are a good seller, before money is released early.
As a new seller money is held for 21 days, or until tracked delivery loaded onto ebay shows as delivered.
If you mean that buyer has paid but you now want to cancel the order and NOT deliver to buyer, then YOU WILL STILL PAY the selling fee, you will have to refund in full and you will get a defect and probably NEGATIVE feedback
Thst is not how you prove to ebay that you are a good seller if you intend to sell in the future.