Thanks for the excellent reports.
The service to Mumbai sounded ridiculous and certainly not the norm for LH F.
In fact, the FA seemed to be deliberately rude to you and your wife. Her response when you asked for an espresso (a basic request) was just plain discourteous. "We'll see"? In F, for that amount of dosh? I don't think so!
I've never experienced German FAs on LH having any sort of language barrier - EVER. They speak perfect English, as do most Germans!
Do not listen to this "Tivoboy" person who told you not to "call her out" - of course you should call her out! She screwed up, not the entire FA brigade that day. Whenever we're given those surveys on LH we have several good things to say about the GOOD FAs. If you don't call her out you will move the blame to other FAs as well.
You did not get what you paid for, which in LH F is basically great service (let's face it, the hard product is not competitive at this stage).
She needs to be corrected of her errors or removed from the F cabin in the end.
I am actually quite surprised with your amount of travel and experience that you did not let the cabin manager know about it early on. I also did not see a rose on your table!
I have been on a few flights where the service is slow or poor but have never been spoken to the way this lady treated you - it seems quite purposeful. I would have been very upset had my own wife been treated this way. There is no excuse for some of her comments and complaints about having to move the cart (well, perhaps next time don't rush things), telling you to pick one starter (never had that happen), and handing you and your wife hot plates or anything else. If you wanted economy class service you could have saved yourselves about 10,000 US each!
Also, anyone flying on an award is to be treated the same as anyone paying with cash. Perhaps you got your miles to spend by flying with them in F on your past 4 trips? Or perhaps the service you get may determine which airline you choose to spend money with for your next flight. Good business would mean the FA should not make any assumptions about a passenger on an award ticket.