Usys Services — threatening to pay 7800

Address:

Chittoor, Andhra Pradesh

I got the online job from quicrr.com, their agent call me and ask my i'd details and they said no registration fees
I asked to payment proofs and sample files but they send a mail and open it after they are saying "you signed the agreement"
And they are saying if you want cancel you pay rs7800 and if we failed to pay they told that they will send legal notice to the home address.
The thing for what i afraid is, they have my aadhar card details and that's why i'm so tensed. Please, help me, my email id [protected]@gmail.com
Please help me please