Absconding from employment without serving notice period

Hi I joined in a company on 18th December 2017 But I didn't like the work much. So I started searching for another job. I got one more offer. I submitted resignation with a polite discussion with my manager on 7th Feb. Which is less than 2months. After discussing with hr they told me to serve a notice period of 2months for my tenure of one and half month. I tried convincing them for immediate relieving but they didn't agree. On 10th I left my laptop there only and left the company. Now the company hr is repeatedly calling and demanding for major amount They sent me a letter that I should pay for 2 months and they have informed my present organisation also. At the time of joining they didn't mention this and I didnt receive any physical appointment letter at joining or in the due course of employment. Please help me in this regard. 1. Is it legal to serve notice period for less than 2months. 2. Is it legal that the company has no probation period 3. Am I liable even I didn't receive appointment letter physically I don't know about that clause where it was mentioned 4. What should I do now. Is there any legal obligation arise for me