Hey @Sylvawavemove, help's here.
It sounds like you either have upgraded another account to Premium, or the charges ended up as pending.
If you got a receipt to an email address, you should log in with that email address. There's more steps here on how you can check for other accounts. We suggest that you have a look.
If the charged ended up as pending, it should be stated on your bank statement where you see the payment. If this is the case, you'll get the funds back to your account after a while, given that you don't get Premium. We suggest that you talk to your bank for more info.
Lastly, keep in mind that the offer is only for users who haven't paid for Premium before. If you haven't, we suggest that you give it another try by opening this link in an incognito window, and choose a different payment method if necessary.
Hope that helps!