Hello Harriet Lemon, Welcome to Microsoft Community. I realize that you've encountered a problem with stopping or changing sharing permissions, and I understand how you feel.
According to your description, it seems that you have tried the steps in this link. Please feel free to correct me if my understanding is wrong.
The instruction doesn't work because the way you share a file or folder is different.
In order to stop or change sharing permissions, please try the following steps:
- Select the file or folder you shared and select Manage Access. (Two ways in the image are both available.)
- In the Manage Access window,
- If you share the file or folder by sending link.
In People tab:
- If you share the file or folder by copying link.
In Links tab:
- If you let anyone with the link can edit when you create the link.
You can remove a link by clicking the recycle bin icon.
- If you let specific people with the link can edit when you create the link.
You can edit access by clicking the gear icon.
In the people list, find the people whose access you want to cancel and click the X.
Feel free to post back if you need further assistance.Best wishes,Lucia Wu - MSFT | Microsoft Community Support Specialist
- If you let anyone with the link can edit when you create the link.
- If you share the file or folder by sending link.