Well....I didn't care if they knew I was Jr. but that is my legal name which is on my passport so that is what I entered. Instead of being like every other company that has a separate block to add suffixes they add it to the last name field. Unless everyone involved from that point forward from MSC employees to TA's enter the name perfectly so it matches their database it will not link and they cannot correct it.
MSC created my profile as John Joe Doe Jr. If the last name field is not entered as "Doe Jr.", precisely including the period, all is lost. The fix is to delete the user account, Voyager account and to reapply for both so they can manually link them together. Then and only then will you be able to manage your cruise on the MSC site and get Voyage credits.