Hello BP community! How is everyone doing?

I need some advice on how to terminate my property manager for failure to maintain an occupancy system with the purpose of satisfying customer demands. My oceanfront studio unit in MB has been sitting empty since the first of November up until today. Zero income for more than 3 months. Whenever I would ask her what's going on, she would give the same garbage answer that our unit is competing with tens of thousands of other units in the low season, that the economy is terrible for travel, that our unit does not have a King bed, etc, etc. 

Background info, back on the 3rd week of October 2022, I sent her an email telling her that we are not renewing our contract and we will take over management starting January 1, 2023. 

Well, that did not go well because she pointed out that as per our contract, it states "

I signed the contract 01/14/2022 but the contract date is 01/06/2022.   

She explained that the contract ends December 31, 2023 which gives them 14 more months of unsatisfactory performance. I asked if there is a buy out and she made me wait 5 weeks for a figure" 4, 300" saying it would be unfair to their staff for the company to lose their commission from our unit since their annual projections operate on the assumptions based on the number of units they manage, yearly blah, blah, blah.

After that exchange, radio silence.... no bookings. When I asked, she gave me the same trash reasons...  

Communication is awful, performance very poor.... Zero income for more than 3 months.... Who would want to stay with them?

Please help me draft a strong and solid letter. My plan is to change the lock tomorrow (I have a co-host from my other unit who helps me with this unit) , The PM gave me non-working door codes today which sent my cleaner home without changing the door lock. After it is changed,  then I will send her the termination email. I would appreciate any and all advice. Thank you!