Usys Services — asking for huge amount money for not completing the work on time.

Hello team,
Please help me as usys services company has filed a case against me for not completing the work from home on time as they were asking for 12.5k penalty which i denied to pay.
They are sending legal messages, calling and torturing daily to pay that amount but i am not having money to pay.
They are cheating people by telling that they will provide job but after that they are doing this kind of misbehavior.