Premium plans are one-time payments and do not auto-renew, so there is nothing to cancel.
Refunds
If you are charged but cannot access Premium, or you are charged twice, email cotactaktutor@gmail.com with your payment ID within [7] days. We will fix access or refund you within [5–7] working days, to the original payment method.
Because Premium content is digital and available immediately, other refund requests are reviewed case by case [or: are not available after access starts].