Fini Technology — harassed by company to pay more

I have taken the work from home project and as per the given time, i have completed the job. Latter came to know from their lawyer that their was errors in accuracy and fine of rs.10, 000/- has to be paid. Which i paid.
Again the same person mailed me and said that your agreement with fini company was 11 months agreement, if you want to continue, continue or else to terminate the contract, you have to pay another rs.15, 500/- to close the case.