The sending of the invoice is instantaneous, have you checked that your invoice has not been sent to your junk mail or your spam? It can happen.
If this is not the case, it is likely that a power outage has occurred between the Payzen server and the Valap.com server. We therefore do not receive the payment information that triggers the generation of the invoice.
In this specific case, we invite you to contact our Customer Service so that we can generate a manual invoice for you. Beforehand, we invite you to check your destination email address. It may be that there is an error hence the non-receipt of your invoice. In this specific case, you must connect to the site, and go to the "My account" tab then "My Orders"; and download the invoice corresponding to your order.