If the company's staff can't get things straight when making a specific number of copies from a piece of artwork it makes me wonder if they're even bothering to type up a basic work order. It should not be on you to solve their organizational problems. Frankly, I'd be kind of alarmed by the situation and worried about ordering shirts from them.
If this shirt company has problems dealing with quantity numbers it would make me even more worried about them handling a non-standard, large canvas mode Adobe Illustrator file. 47 meters is a little over 1850 inches. The max art board size in a normal Illustrator file goes no larger than 227" x 227". The large canvas mode bumps the maximum to 2275" X 2275". But not every third party shop or industry specific piece of software can handle those kinds of files or PDF files generated from them. The sizes may get dropped to 10% of their normal size when imported into another application (if the artwork imports at all).
Regarding what file format to use, it depends on this shirt company's setup. Are they using Creative Cloud applications like Adobe Illustrator? Or are they trying to import customer provided art into apps not made by Adobe? If they're taking customer provided PDF files as is direct to print does their print software have an Adobe certified PDF print engine? They may not know right off hand, but if they tell you the name of the application they use then it would be easy enough to find out online.