Evict with no written contract cont.?

The house is mine and my husband, we live there with our kids, and they rent part of the basement from us. We are the landlords, they are the tenants. It is my husbands cousin and fiance, and they had their mailing address changed. They have no bills tied to the house, only their own personal bills. Last night 1/15/09 my husband gave them 2 weeks notice due to irreconcilable differences, and now they are threatening lawyers saying they legally have 30 days due to their mail being sent to my house. Help Me Please!!