Hola Gyan, You could try also using the more unformal way (tú in place of vd.) - ¿Perdona? ¿Disculpa? As for the pronunciation, I find Forvo website very useful with pronunciations in different languages: https://es.forvo.com/search/disculpa/ Hope it helps!

A veces, esa aplicación tiene errores y considera respuestas correctas como incorrectas. Es algo que ellos deben mejorar. Si dices DISCULPE o DISCULPA estás dando la respuesta correcta. Asi que no te preocupes y sigue aprendiendo. Saludos

Hola! Your guess is pretty correct, disculpe has a much more polite sense and it's directed to a particular person who you treat with due respect. However, Perdon is a more generic term to refer to general public or even a person. It's similar to use Sorry in English. Hope it makes sense. BTW Gyan I'm looking for someone to do a Tandem in French. If you know anyone who wants to practice Spanish or English. in exchange of French please do let me know.

What do you mean you can't get it correct? Do you use a Spanish keyboard?