Ketogo Tried to Charge Me Again After I Canceled Subscription

I downloaded the Ketogo app on my Android phone out of curiosity and signed up to try it. After a short time, I decided not to continue and canceled my subscription. Despite this, €39 was charged to my card last month. I contacted the app, requested cancellation and a refund, and they returned this amount within about a week.

However, today, even though there is no money available on my card, another attempt was made to charge €39. I do not accept that my card is being charged again despite canceling my subscription and already receiving a refund.

I request that my membership with the Ketogo app be permanently canceled, that my card information be completely deleted from their system, and that no further charge attempts be made under any circumstances. I also request a written explanation regarding this situation.