Hi @Ezequiel80, welcome to the forum and thanks for posting.
Sorry that you are having a problem viewing your bill online. Have a look at How to View Your BT Bill Online and see if that helps. If the payment was made after your last bill it won't show until your next bill.
If the payment was made before your last bill and does not show were you asked to pay a deposit that would be refunded to you at a future date?