You have two choices:
1. Support the DRM style monopoly of that specific brand of printer. Buy their printer and continue buying their filament.
2. Vote with your wallet by buying another brand printer and then telling XYZ that you did and why.
Actually you generally have 3 choices.

3) go on youtube and watch a video on how to convert your drm machine to opensource filament. Pretty much all the desktop systems have been 'jailbroken' as it were.
In some cases you can actually print a little doohickey that reroutes the filament from a standard spool through the propriatary cartridge - I think I saw that on a davinci printer of some description. In others you might have to hack the cartridge itself. But there are a lot of ingenious people out there who spend a lot of time on this sort of thing.