Ask the server's owner. They were paid directly — the money went into their own Stripe account and flatpass never held it — so they are the only ones who can return it.
The server’s owner. Your payment went to them directly, so they are the only ones who can return it, and whether they do is their decision.
Ask them in the server. Tell them which tier you bought and when.
Cancelling stops the next payment and leaves your role until the period you paid for ends. It returns nothing. If you want your money back, ask for a refund.
A chargeback with your bank takes your role off at once and keeps it off while the case is open.
Run /membership in the server and press Manage billing, or use the manage link on the server's invite page. The role stays until the period you've paid for ends.
Run /membership, press Manage billing, and update the payment method in Stripe's portal. A failed renewal keeps your role while Stripe retries.
Yes, from the server's invite page: billing stops and the role comes off until you resume, and you keep the plan and price you had. Not during a free trial.