Udkon Infotech Pvt Ltd — Payment not given and no response when calling through work done in timetime

I have seen about this company on YouTube.i have done offline handwriting work for 8 days i.e.from 17 th April to 24th April .they said they will give my payment after my papers verification on 29th April.they have even collected 1800rs as security amount from me which they said is refundable.but now when I'm calling them, they are not responding nor replying to my messages.i have submitted my papers in time..If my papers are not verified, they should atleast message me and inform me that they will pay later..but there no reponse.. so, please help me to get my payment and security amount