I was very surprised: Klaviyo billed me 3 times for the same period. When I contacted support, they mentioned that due to auto upgrades and downgrades within minutes, there is a technical mechanism that invoices the user multiple times. So I asked for a refund as it was clearly a technical error. However, there seems to be no leeway to fix this error. Klaviyo never reimbursed the overcharge. This is very frustrating for me and I don't understand this "customer service" at all ... very disappointed, Klaviyo!