Management Issue - Appointment Letter

Hello Dear People,
I need your help.
I am working in a Chemical Company (head office) in Mumbai as Sr. HR Executive since 7 months.
I am not satisfied with the job and not with the culture. It is typically very dominant culture with no scope of learning new things.
I had a discussion with Managing Director and resigned verbally on 7th September 2015 and he accepted as well. I have also requested to relieve me by 16th September 2015. FYI, I am in probation period and there is no policy in my Appointment Letter regarding notice period in probation. I didn’t write the resignation letter because things may turn out against me.
Now, the company has not processed my August month salary and trying to retain me as well. I am currently working in the same company however I have made up my mind of leaving this job.
Kindly suggest what I should do?

Put up a written resignation on immediate basis.
You are on probation and the appointment letter does not prescribe any particular notice period.
Meet the MD and directly but politely ask him why your pay for 08/15 is being held up??
If you are not happy,then best is to leave.
Or just wait for few days get your monthly pay and then quit in October without notice.
Off course company may not give you proper release documents.
Anyway they are behaving oddly and you are left with no reasonable choice for mutually settled exit.

Yes, I am working on roll of the company and I have also tried to talk to the management but nobody is giving me any kind of specific answers.

Dear Mr. Nathrao,
Thank you for your advice. I requested them to release my August month Salary which they provided me on 25th September 2015.
They are trying to retain me because their is no other person in HR except me.
I am planning to get the monthly pay of September 2015 and talk to them the very next day and leave.
I am also sure, I wont be getting the relieving letter or experience letter which will become a serious problem in my new employment in near future. They didnt give Salary Slip as well.
Moreover 1 May ( Maharashtra Diwas), 2nd October (Mahatma Gandhi Jayanti) these days are working day. We dont even get the national holidays.
How do I convince them for providing the Experience Letter?