Problem Solved: Microsoft is making it hard to get a replacement part
https://www.siliconvalley.com/2019/04/07/why-wont-microsoft-pay-for-a-missing-pen-tip-on-my-surface-4-pen/
Q: I need help getting a refund from Microsoft. I have a Surface 3 tablet and a Surface 4 pen. Last year, when it was still under warranty, the pen completely
stopped working. I contacted Surface support, and they said they’d send a replacement as long as I shipped the defective one back to them.