Regarding experience letter and relieving letter denial by company if I break 2 year bond

Hi All, First of all thank you for taking your time to answer this question. I have signed a appointment letter with company of 2 years with so and so salary structure. It was not a legal bond. I have following questions. 1- My company's delivery head recently told me on telephonic conversation that I could leave the company if I am not happy with the current salary structure however they will not give me my reliving letter and experience letter and it is mentioned in the appointment letter. So can they deny giving me reliving letter and experience letter on the basis of the appointment letter/bond? There are only 6 months remaining for this so called bond to end. 2- in the appointment letter which I signed, the notice period was only 1 month however after 5-6 months company has changed its policy for all employees and now the notice period is 3 months, so which period should be applicable to me legally. 3- If I resign 1-2 months before my 2 year completion date And serve the 3 months notice period, which means I have left the company after total 2 years and 1 month, is that appointment letter/bond still valid and can they deny giving me my experience letter and reliving letter? 4- how much is the legal timeframe for one company to actually release these experience letter/ reliving letter/ other documents if an employee has resigned from the company. Kindly request you to address all of my above questions.