Tenant didn't sign lease

[Ryan Proffit]

Hello team,

I acquired an 8 plex about a month ago.  The in place tenants were month to month.  We drafted a new lease with a rent increase and instructed the tenants to return the signed leases by Jan 1st.  I have one tenant, who went ahead and paid the increased rent, but hasn't returned the lease.  I have text her, called her and left a voice mail on Jan 1 telling her that she would be considered month to month at a higher rate, but no response. 

How should I proceed?  I am fully aware that she can't just stay in place with no lease.  That scenario seems less than ideal.  Let me know.  Feel free to let me have it.  Thanks.