Oil loss on the automatic transmission

The other day, I found oil loss on the gearbox of my A8. Since I still have a guarantee, I went straight to the friendly to have it beaten.

But since the car was bought from another brand dealer, they didn't really know about the thing. Their mechanic said that you probably have to have another (overhauled) gearbox installed, also because you have a lifetime oil filling at Audi which is not so easy to refill. But, as I said, they don't really know each other that way. So they took the car to an Audi workshop. (It is more likely to be annoyed, as they had to pay a bill for the exchange of a mass cable in the amount of 200 euros).

After four days in the four-cylinder car rental we got our unwashed car back. With an old transmission, into which the missing oil was filled with a probe and the hole was "sealed".

Now to my question: Is this the normal procedure for such (almost) gearbox damage, or should it have been an exchange gearbox? Because I tend to assume that they want to save at my expense in the wrong place (a new drive would certainly have been much more expensive than this rum-based drive). I see myself standing on the stand two months after the end of the warranty period with defective automatic...

Greetings, Claudia