California credit-card purchase went wrong: can I dispute the charge?

Potentially. California Attorney General guidance explains that federal credit-card rules allow billing-error disputes and, in some cases, claims and defenses when goods or services were not provided as agreed and the seller will not fix the problem. Deadlines and conditions apply, so keep receipts, statements, emails, letters and photos. Official source: California Attorney General Credit Cards — Disputing a Charge. Guide: https://getinstantlaw.com/us/california/consumer-rights