Personal job solutions - Demanding unnecessary penalty

I got a call from a company personal job solution to do freelancer work to which i agreed, they told me to sign a digital signature on the agreement from the company without giving me the proper details that if I in any case cannot complete the work then I have to pay **** rs and now they are demanding and harassing me through calls and chats to give them the penalty.I could not complete the work because there is a fault in my laptop which I will address later but they are now pressurising me to give them the penalty.