Getting a human being to deal with your problem is unlikely, unless you

a) stand at the counter - and even then they may be unable or too indifferent to help. More so AF than LH
b) are a top tier customer in their FFP, in which case LH has a dedicated customer care centre. AF doesn't
c) are just plain lucky

There is a "brutal" way to do this: ask the credit card company not to pay for the AF ticket. Like that AF will "wake up" and deal with you, and hopefully give you the confirmation of the re-booking. You then can provide that to LH.

Good luck.