Call off marriage after Roka ceremony.

My name is Pardeep Singh I'm 26 year old working in Delhi In the January of this year I got engaged (ROKA) with a girl. Girl is from Amritsar, Punjab. She has done M.A (Punjabi) and according to her Family she wanted to pursue B.Ed/Msc. The day I went to see her she was looking beautiful. I promised her if she want to pursue her B.ed /Msc or career I and my family would always support her. I didn't talked much with the girl due to my busy schedule or late night shifts our Roka happened on 25th jan 2016, but marriage date need to be fixed yet around nov-dec of this year. Actually I had an expectation of marrying a professionally settled girl who can respect my family too. As I was thinking that I will get her B.ed/Msc done after marriage and after that she will be having her own professional identity. But when I started talking to her over the phone, There were lots compatibility issues and intellectual mismatches. she has done M.A but while talking to her I never felt this. It was like if I'm talking to a high school girl studied in Punjabi medium. also she is no even clear her mind what to do after M.A. she always changed the topic I understood that she is not meant for me. I told my family about this but since ROKA had already happened they pressured me saying what others will think and about social shame. and insisted for marrying the same girl. It happened 3-4 times in last 3 months. Finally last week I had long conversation at my home and told that I didn't want to marry her also told the the girl and her family about my decision, that I could not marry her and even If I marry her under social pressure It would not be good for the future of our both and later a situation of divorce might occur. Now I know that there are few mistakes from my side that I should not have said yes for marriage just by seeing her one time.and after talking to her If it was clear in my mind not to marry her I should have taken this step 3 months ago what I did today. ( informing her). Now I'm worried that If her family could defame us in any case. most probably I guess is they will try to defame us under fake a case of dowry demand and they already told to my parents that sake compensation more then they spend on Roka ceremony. If I asked her I want to meet you she directly indirectly said no or let me discuss with my parents. Let me clear that I hadn't met the girl single time after Roka ceremony held. My parents said that you humiliate us. Please, tell me solution ASAP I'm very nervous at that time.