We have been using Klaviyo since 2018, Never had issues with them up until today...When going through their different billing plans, accidentally upgraded our plan. Out team immediately took action, and e-mailed Klaviyo support, within less than 1hour of upgrading the billing account. To our surprise, Klaviyo responded back to us with a "template" e-mail. Saying that according to their T&C we cannot get our money back. NOTE: We e-mailed Klaviyo immediately after changing our billing plan. NO email were sent to customer, to account for plan usage. There are other alternatives out there, we have been looking at Sendlane.