How get I either use or withdraw “balance” money in my account? It’s not from selling, it’s from cancelled orders.
Order more orders and cancel them in a Faustian loop of pointlessness.
Or set up a PayPal dispute, get your $50 back and get kicked off Fiverr forevermore (see their Tos). Your choice!
PS don’t cancel too much or you’ll be kicked off anyway. Might still be able to get that PP dispute, but since F/PP are in some merry cahoots with each other, the evidence will probably be weighted and you’ll be left to scream on thousands of review sites only read by people who are already teed off.