Resignation during probation period

Hi, I joined a local automobile dealership at a senior position. I left them under probation period without serving the notice period and just whtsapping that I can't continue under the given conditions. I was mentally tortured by my employer so I left it . In my appointment letter it is mentioned that my probation period is of 6 mths and notice period is 30 days . It doesnt talk about resignation under probation period . I was also asked at the time of employment to submit 3 signed cheques and 3 signed blank papers as a security . I submitted it as I was in need of job. It was also done with other candidates who joined with me. I also didn't take my last month salary when I left this dealership. Now it's been over 3 mnths and this dealership owner has put one of the cheque in my bank with recovery amount of 1.81 lacs. When I went to meet him he said that he wants me to reimburse the salary which he paid me for the period i worked there and also the training cost he incurred for me . I've never ever left any of my previous organisations this way . I left this organisation coz I never used to get salary on time , I used to do work which I wasn't required and also the abusive behaviour and language of the dealership owner. I m being mentally harassed by the HR and owner of dealership. Please help and suggest.