How do I fight my previous employer for not paying me my 2 weeks notice like they said they would?

I gave my previous employer a written 2 weeks notice last week, stating my last day would be October 9th. When I turned in my notice, my manager told me to go ahead and turn in my stuff and go home. He said that I would be paid for the remainder of my notice, but that because of the nature of the business, they did not want me to actually work out my 2 weeks. I received my paycheck today and it was only for the days prior to the day I turned in my notice. I called my manager and he directed me to the HR manager, who said that I did not receive payment because I have not yet reached 90 days, so they were not required to pay me. They did not tell me that and I was willing to work until my last day, which they would not let me do. My manager specifically told me that they would pay me for the next 2 weeks, even telling me that I should take 2 weeks off before starting my new job because I would still be getting a paycheck. Is there anything I can do now?