Representative payee portal doesn't appear

Social Security named me as representative payee for my disabled son seven months ago but the "representative payee portal" option doesn't appear on the My Social Security page. I received the appointment letter, have received the payments and have set up special accounts for them, so those should not be issues. The social security representatives I spoke with by phone were nice, but seem to be baffled as to why no portal option appears on my account page. Has anybody experienced (and-or solved) such a problem? I am worried about missing messages or announcements since the mail is not reliable where I am.