Support
Use this page for a problem with a Plus or Premium payment or with your account: a charge you don't recognise, a plan that didn't switch on after you paid, or trouble signing in. Each message becomes a numbered ticket, shown on screen when you send it; the reply comes by email from the owner, with no response time promised.
To update your card, see your invoices or cancel, use the Manage subscription button on your account page, which opens Stripe's billing page; how billing, trials and cancellation work is in the terms. For a wrong price, a missing store or an idea, the contact page is the better place.