Company Threatening To Take Action To Get Money As I Had To Leave My Job Urgently Due To Famiy Issue

I am 32 with 18 months baby.He is unwell and my husband stays in different city due to his work.I had to leave my job and urgently travel to take care of my husband who is unwell and was staying alone.I informed my manager on phone and had discussion two times on the same issue. When I was hired, I was hired at a pkg of 8 lakhs and later on the company asked me to work on a lower pay of 5 lakh when they did not have the budget to continue the project.I even cleared certifications required to work in an advisory firm.Now I have email from legal advisor of the company that I need to pay the compensation for non serving notice.I used to the reporting work only and no major task was assigned.Hence there is no major loss to them in financial matters.Neither do I possess any company asset with me. When I received the offer letter with reduced pay, there was no mention of pay up in that, it was the revised payroll letter.Do I still owe the company any money and what legal action can they take against me.