There are two main reasons for double debits:
1) several different payment methods were added to your account;
2) Moonly Plus monthly or annual subscription was not canceled after the Lifetime purchase.
If you were charged twice, please contact us via the Support section and send payment receipts for both payments. You may find these receipts with the purchase confirmation via your e-mail inbox or via reportaproblem.apple.com (iOS) / pay.google.com (Android).
We will check your Moonly account and help with the refund 🌕✨