Pam, you don't need advice at all!!
That was like talking to myself! That is what I would say.

If you want her to stop this you have to make it less fun for her.
You can do this several ways. Put her on a lead and take her to the bathroom. As soon as she starts on th loo roll you choose which method is most likely to get her attention.
1 - Water spray
2 - Can of pennies or stones
3 - Lead correction

Use your voice as well. "No, leave it!"
As soon as she leaves the loo roll, "Good girl."
When she is safe on the lead leave a can of pennies or stones by the bathroom door so you can give it a good shake if she returns to this behaviour when off the lead.

Or...you could shut the bathroom door!