No experience letter for a contractor position- despite working the equivalent of an employee.

I worked as a contracted counseling psychologist at United Health Group's Optum Health and Technology for 15 months, ie. May 2016-May 2017+ June, July and August. The operations manager informed me that United Health Group and it's company Optum Health and Technology does not issue 'recommendations'. Moreover he went on to explain, that since I was in a contractor's post, I am like a freelancer and not an employee and hence I am not entitled to an experience letter. Facts: 1) I have worked the equivalent of the regular employees , given 30 days notice as required, and I have recorded minutes the meeting where I was verbally assured of an experience letter. 2) The company did not give me any document of an extended contract or a renewed contract, after my original one expired on May 15th 2017. Questions: 1) Am I entitled to receive an experience letter , despite the 'policies' or 'practices' of an MNC ? 2) I was not informed of being like a 'freelancer' until I gave my notice to the company. Does this become relevant in my request for an experience letter? 3) I have maintained call records of certain nasty conversations that happened in the last few days of my notice period. Would this be of any use in something as simple as a request for an experience letter? I intend to write an email/ registered letter to the company requesting them to send a copy of an experience letter to my address. However I would like to know my rights or be prepared for any unexpected interpretations of it, before I send such a request to the company. Thanking any lawyer who replies to this, in advance!