I had much the same problem a few months ago with eresmas (which is billed by Wanadoo). The solution I was given was to add "@adsl" after the ADSL IP access identifier, after the SMTP mail server, and after the POP3 mail server.
No formal warning or notification was ever sent, so it makes me think they just want to collect from 902 calls.
Hope this helps.
No veo que quieres decir por "ADSL IP access identifier". No encuentro nada de eso en mis "settings". I para el POP3 mail server ¿qué pongo? Si he entendido bién sería "pop.wanadoo.es@adsl". Con eso no se conecta al servidor.