Company is not providing the reliving letter/Experience Letter

Hi, I worked in an IT Software company for 4 months. I sent the resignation mail to my manager. But neither he accepted nor he declined even I followed him lots of time during my notice period but he didn't reply.I went to HR but she was also not providing me No dues certificate. Than I submitted company belongs to the HR person and left the company I am not going to office as per my resignation date. I tried to contact them to provide me my relieving letter.But they are not releasing. And saying you have not followed the company rules so we can not release the relieving letter. But I followed everything and they fall me on each and every points. 1. Without any approval you are not coming to office - I sent the the relieving letter but they not replied to my mail. 2. No dues is not completed from your side. - I went to HR person but she not provided me the no dues certificate even after submitting the all the belongs. Even in HR company policy book is written If you wants to leave company immediately you have to submit the 1 month salary. My notice period(last) month salary is still due from the company. I said don't give my last month salary and provide me the relieving letter. But they agreed on this point also. My New company also not allowing me to join without previous company relieving letter. They are behaving/talking completely unprofessional way. Please help me...How can I get the relieving letter from my previous company?