Math is developing, and we expand our understanding of it as well. But that does not mean that it is not black and white. A statement made in mathematics means one thing and one thing only, and that thing that it means is... what it means. Mathematics is a very straightforward language. That is why physicists use it to express reality. They are not trying to describe the universe in confusing ways, they are trying to describe it in ways that are understood by all. That is why they use mathematics.
Scientists are not confined by mathematics, they are confined by their understanding of the universe. One of the most basic tenets of modern science is that the all natural phenomena can be described by mathematical laws. If the universe acts according to laws that are constant, then it can be described by mathematics. We assume that the universe does act according to these laws. If it did not, then we'd be right boned trying to understand it.