Security blank cheque taken from for service agreement bond

Sir iam a fresher Btech in Computer Science & Engineering and i was placed in 4 year in a company in delhi and had been working there as intern according to my offer letter and at the time of joining they take a blank signed cheque of rs 70000 from me and bond is of 20 months they didn't give me the copy of bond and also in my job they didn't give me any kind of training one of their employee was just guiding few new joiners only for about 20-25 days but after 5 months i left the company and i also make stop payment of my cheque and after 1 month they send me a notice from an advocate to pay 70000 plus 18% interest plus 31000 of the notice so i replied that through a notice from my advocate about which allegations were not right and its now 3 months since i went to office and in between that period they submitted my cheque in bank and was stopped and after some days they sent me the notice again from a lawyer that i have to pay 70000 rs plus some penalty otherwise they will file a criminal case against me under section 138 to 142 of negotiable instrument act and section 420 ipc and they also mentioned in notice that if i will not make payment then i will be sent to jail Sir please guide me as this all is like a torture to my mind iam not able to do anything properly Iam getting depressed due to all this and iam getting negative thoughts as well Please Guide me