A family of Microsoft word processing software products for creating web, email, and print documents.
Your description suggests that the list formatting is broken. Sometimes, copying formatting (Ctrl+Shift+C) from a known "good" list and pasting formatting (Ctrl+Shift+V) can improve the situation.
However, the easiest way to fix this is to start fresh: Set up a multilevel list so that you can have higher levels restart lower ones. Associate each level of the list with a unique paragraph style and apply the paragraph styles to apply numbering.
For more, see https://shaunakelly.com/word/numbering/numbering20072010.html.