HTML code not showing in broadcast email

Max Classic
2 
 <div style="background:#bf121a; color:#fff; font-size:20px; text-align:center; padding:20px 0px 20px 0px; width:100%">
    PARA ACTUALIZAR TU MARCA COMUNÍCATE AL
</div>
 <div style="background:#bf121a; color:#fff; font-size:25px; text-align:center; padding:20px 0px 20px 0px; width:100%">+573123778157
</div>
<div style="background:#bf121a; color:#fff; font-size:20px; text-align:center; padding:20px 0px 20px 0px; width:100%">Ó escribe a:
   <EMAIL mailto="avargas@giraffeideas.com">avargas@giraffeideas.com</EMAIL>
</div>

standard mailto links aren’t compatible in XML. That being said, mailto links with a subject parameter will probably be stripped by most email clients.