But no, we have never received such a feedback before. We use a third-party payment provider (Paddle) exactly to have the maximum security possible for the transactions, and they are transmitted on secure and fully encrypted channels. So I definetely think this is an inconvenient coincidence.
To avoid any doubt and concern, we will investigate anyway and enquire with Paddle. Better not leave anything to chance here.
Of course, my suggestion is to block the card immediately and contact your bank to notify them about this (you might have an insurance on your card which allows you to get back the amount).