I don't think you don't have a leg to stand on. In the absence of a written lease, your landlord does not need a reason to terminate your tenancy as long as proper notice is given. In this case, it sounds like proper notice would have been a 30 Day Notice of Termination served by a process server. The rodent and cockroach stories aren't necessarily relevant.
It seems your landlord prefers tenants that don't complain.

