Billing after trail period

I have just subscribed for the first time. I have 3 days left on the trial period and paid for the basic plan today . It says that the plan will start when the trial period is over. I entered payment details but got no invoice or receipt of payment by email or no notification. Does anyone know if they send an invoice after the trial period ends ? Is it that payment has not gone through until then>? Impossible to get in touch with anyone in Ring!