No written agreement makes this a problem. I would advise you to consult with your landlord. If you sublet without your landlord's knowledge or approval, that creates another set of problems, which may result in your eviction. EIther way, I'd suggest you consult with an eviction attorney in your area. You might also consider calling your Local Tenant's Rights people. They can tell you what your rights are and what your sublet tenant's are. Good luck.