@Carmen1479
You can't change the rules after a booking has been made.
Your only options are to
1) message the guest and say that there will be no toilet paper - But then they can claim money back via Airbnb as an amenity has not been provided
2) message the gust and ask them to bring their own which you will refund
3) do nothing and hope for the best
If I were a guest then I would prefer option 2.
Bear in mind that they may be able to cancel without penalty anyway depending when they booked/when they are staying