If you have bought credits by official shop of incomedia (by 2checkout) you had it in your emailbox (or in spam folder).

Hello. I sent a notification about your question to the company employees, expect an answer from them here in the comments.

Hola Eduardo, 

gracias por tu mensaje. 

Hemos enviado la factura a tu correo. ¿La has recibido?

¡Gracias! Cordialmente.