One of the best explanations for this would be that the viscous ink inside the cartridges cannot flow as well as needed. Additionally, several ballpoint pens can stop working when the unused ink left inside exposes to air. This, in turn, dries up the ink and makes it clogged. As a result, the ballpoint pens stop working. You can either change the cartridges or heat the tip so that the clogged ink loosens and starts flowing easily. Moreover, if you are buying a low-quality product it will not work for long. Therefore we always recommend buying from trusted suppliers or sellers.