I mean that if you don't speak German to a professional level then there are limits to what an MBA will do for you, especially an MBA that is not very strong. Very strong MBAs are expensive to run, and thus employers for MBA-type roles value the added value that thse top MBA programs see and develop in top-quality managers. There are funding optipns, mainly loans, for people who can't afford these programs in advance. Without the ability to pay fees, you are limited, as you have discovered.
Furtwagen has a small programme, and if you listen to the sample videos you will see that it's not taught like an MBA: the information comes from the lecturer; there's little questioning of the students, their background knowledge seems limited when they do speak, there's certainly no sign of methods which really build critical reasoning or verbal acuity. This programme cannot develop many people who are qualitatively better at working like a modern MBA. Just look at this:
https://www.youtube.com/watch?v=9zQTC8bBEhsHFU, FAU and Reutlingen are not all in the same state, by the way. Furtwagen is in Baden-Wuttemburg.