Macan Transfer Box Issue

Porsche Cars GB Ltd are telling me service campaign WLE9 (transfer box fluid change) is totally unrelated to transfer box failure. I’m arguing both are inextricably linked, do any of you Pistonheads have documentary proof of this, which would have been supplied to ALL Porsche Centres in UK. Maybe some nice guy/gal in dealer would supply this? anonymously of course. rod.plumb@yahoo.com Thank you.