short term rental landlord emailed I am to be out tomorrow

Hi
I rented an apartment for 3 months through an online rental agency. I had believed everything would be handled by the agency instead I have had to work with the landlord who at move in time had just started to clean the apartment which took him 4 hours to do. Then to handle a repair a few days later he did not come in the morning as arranged, instead at 23:00 unannounced with a few of his friends who all came into the apartment. I complained to him about this as being unprofessional and inconsiderate. He is now angry and emailed me many insults and has advised me that I must be out tomorrow because he does not want to rent to me. I have paid in full the deposit and first months rent.
What rights do I have? I myself could not (per the agency information) have cancelled any of my stay without forfeiting all of the deposit and, I believe, being liable for paying the full rental amount.
If I can stay am I able to change the lock to prevent him from entering? I would replace the new lock with his original lock at time of move out. Is this allowed for me to do?
Thanks