The primary thing is that your exit from that company is not proper and you had left just by sending an email to them. This is not right what so ever personal reasons you may had that time. Though you have not signed any offer letter/appointment letter you admit that you have worked there for one month, signed the attendance register, emailed them your resignation letter which are all proof you were part of that Company. Now that you have left them abruptly they can serve disciplinary letters like warning/termination based on your email. Even they can communicate to your future employer (if they come to know where you have joined) about your improper relieving.
However in the absence of offer letter/proper Appointment order there will no legal validity much. No need to worry about their calls. However please ensure that they should not manipulate your exit as " absconded with company property/valuables "(for which also they should substantiate it)
12th July 2019 From India, Madras
Thanks. I have communicated them in a positive way that my support will be there and will be contact with you in future also. I have handovered all assigned company assets. But now he is harrassing me that tell me your company name so I will send notices to them also. Also, I am not mentioning this tenure of experience on my employment records. How to deal with it, please help me out?
13th July 2019 From India, Hyderabad