How do I close one of shared broken washrooms that the tenant insists it is belonging to her rental unit

How do I close one broken(water leaking) of shared washrooms that the tenant insists it is belonging to her rental unit. She does not response my asking. My utility bill price is abnormally high.

According to the attached guide line #19, I can access to the rental unit (actually the washroom is not rental unit) with 24 hours before notification.

My tenant, YOON, has sub-rented only unit B1 to her tenant WELAH for 7 or 8 years. However, WELAH has occupied unit B2 and one shared washroom since 2019, or 2018. I and YOON agreed to end of tenancy for whole basement April 30, 2020. I and YOON asked to empty unit B2 and allow to access shared washroom. She has refused and insisted the unit B1, B2 and the shared washroom is a set of rental unit. I or YOON never agreed with that kind of agreements. There is no written agreement. However, several visitors have used the unit B2 for several years.
I know that is clear evidence. However, I and YOON couldn't contact the visitors who stayed before.I applied hearing with N12 form ( but the hearing is not scheduled yet because of COVID19). LTB(Landlord and Tenant Board) answered I didn't write exact unit number (because WELAH occupy unit B1 legally but unit B2/shared washroom illegally.I notified N4 form (Eviction request end of July 2020 ) to WELAH.The problem is my water bill is too much high (over $2700 ). I suspected the washroom beside unit B1 has water leaking. Thus, I asked to access to inspect and repair it. However, she didn't answer. She insisted to talk her lawyer but her lawyer has no answer.I left a notification to inspect it on July 21 to access on July 24, 2020 09:00 - 12:00. ( which I complied regulation 19 of LTB )