If a product does not work as its listing describes, you are entitled to a refund. Ask through the purchase's receipt page within 14 days of the purchase; where consumer law gives you longer or wider rights, that law wins.
Subscriptions are refunded pro rata only where the law requires it; otherwise cancellation stops the next renewal and access continues to the end of the paid period.
A refunded purchase revokes the entitlement it created. The product is told, through the same webhook it was told about the purchase with.
Disputing with your bank instead of asking us is slower for everyone and can suspend your access while the dispute is open. If a dispute is lost, the entitlement is revoked and the amount is reversed from the builder's balance.