From the order page, where there is a form for it, or by email to support@lempart.app with your order number.
Tell us what happened. If the eSIM did not work, say where you were and what your phone showed — that is what lets us fix it for you and for the next traveller.
We check whether the eSIM was installed and whether any data was used, as the network reports it. Then a person decides and answers.