lease/owner finance

[hbujak]

we are buying our home via owner finance from his parents. We have not paid the rent for December because we will not have the money until Friday. We notified them on November 30th that the rent would not be paid until 12/7/2007. They are now harrassing us. They call my husband tons of times during the day, came to our house. Today we recieved a letter from them giving us a 3 day forcible detainer. They claim we are in breach of our contract for non rental payment along with several other items that are not true. Could you please tell me what my rights are in the state of texas? We can not afford an attorney and we have three small children.