Did your lease state you could be given less than 3 days notice, even though the guy is calling it a 3 day notice? Review the lease, talk to a lawyer offline in your area ASAP then. Best of luck
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The notice could be invalid, however many justice court judges will allow the flaw if the landlord actually gives you the three days. You should certainly fight the notice if an eviction is filed. However in the long run if you are behind in rent and cannot come to an agreement with the landlord, in writing, then eventually the landlord will prevail and have you evicted. You should have your lease and the situation reviewed by an attorney in a free consultation. You can obtain full representation for around $500 with assistance after the matter is resolved.