Every University has an allotted time frame for a particular course. For example if a course is for 3 years, you are supposed to complete it within atleast 5 years. Or else you will have to register for the course once again and complete the course. If you were from 2012 batch, this is 2020 and you need to clear 6 backlogs all at once. If you think, you cannot do it, you can always study through Distance Education where you can study at your own pace. But again the validity of each admission remains the same. So take up a course that you are interested in and study it through Distance Education.