About relieving letter

I have been working in CMM L3 organization from 5 months. My probationary period is for 6 months. Due to my manager act i wanted to resign my self and get out of the organization and sent resignation. I have stated the reason as personal issues, but every one knows the reason why i am leaving. Even HR and CEO asked me again and again that "do u want to complain on the Manager?" i stick to my earlier argument that my resignation is due to personal reasons because i don't want to complain on any one and do any messy and i said that ill serve notice period as per the policy and leave. Then CEO told me no need to serve notice and you can go now. Right after i got an email from HR stating that i need to serve notice period for 15 days. (Note: If i serve 1 month i will finish my 6 months tenure). I have served my notice and its my final day according to their mail for notice period. When i asked for my relieving letter, my HR says that i won't get any kind of letters as per the company norms. I asked that what is the point of serving 15 days notice period then if i won't get any documents. When i asked about salary, she said i would get after 45 days. I don't know whether i get it or not. After serving the notice period according to their mail and today they are talking like this. Even i heard from other employees informally that company won't give and harass people like this. I don't know its Level-3 CMMI and how can they turn their words and doing all this us. I don't know how to proceed now. Can any one please help me how to process. I have their email copy asking for notice period.