What are grounds of mental harassment

We have common toilets in my pg and there have been some situation of uncleanliness by the pg mates in the past which all of us were facing. On one occasion I was unable to leave the toilet clean so I informed some of the girls and they suggested me some ways of cleaning, which I did and thereafter followed regularly. However, recently such case of uncleanliness has been occurring again and those bunch of girls are blaming me and and telling other girls and the owner about the same without any proof. It is really humiliating for me to go through this everyday. I am scared to use the toilet in pg because they are trying to look for opportunities to blame me. I would like to know if this is a case of mental harassment so that I can discuss it with the owner as she is closer to those girls because they have been living here for a longer period of time. Any time the toilets are not clean they say I am purposefully doing it to irritate them. I don't understand how to act in such a situation