Thanks ModulosDePago.
@Edurne : HikaShop didn't develop the plugin, so we can't provide support on it, like you can understand.
Please see with ModulosDePago and their support directly.
Please also understand that we don't speak and provide support in Spanish ; this forum is fully in English except for the section "HikaShop around the world".
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.