Exa Technology — demanding money

I have applied for data entry job . I have done half work with some problems i have not done the work which they have given to me and after that they have called me asked money for penalty so i have paid them the penalty. On that day they have said your file has been closed there no problem further in future. But again they are asking money about 28500 as a student how can i pay that huge amount please help . Thank you