Hi there.
@henrikbjorn is right. There’s 7 days window period until the transaction goes from pending to complete or cancel.
If the transaction is pending means that the merchant has not either collected the funds nor declined the transaction.
There are two possible scenarios now: either they will realise the error and decline it, or they will not realise the error and will settle the transaction.
When that happens, you will be able to see that the transaction no longer appears in grey in your transaction history on the app. Then you can just let us know and we will be able to raise a chargeback on your behalf to recoup the funds.