Wife threatening to file 498A and DV

I am a 30 year old, got married in 2018. My wife's parents demanded money from us and after we refused, she used to quarrel over petty issues throughout the past year. This year she left my house on the pretext of visiting her parents for a few days but did not come back. It has been 3 months. She sent me legal notice threatening to file 498A, 306 and DV against me & parents if I do not pay her 1 lakh/mnth. I do not have an income as my business is in a loss. It was supposed to be profitable this year but due to pandemic and lockdown, the situation is worse. She has engineering degree and was working before and after the marriage also. She had a salary of 15k per month. Now she may have quit the job in order to extract maintenance from me. What to do? Will I have to pay even if I don't have any income source? What If I an unable to pay? Can she claim from my parents' income? Lastly, What should be the approx cost of fighting this battle as I may need to borrow to pay legal fee.