Hey.

There are lot o college which do accept a student with an aggregate percentage  between 70-80% for BA MASS COMM.HONS. in Kolkata. Here are a few of them:

1. ST.XAVIER COLLEGE
2. Ashutosh College
3. Presidency College

These are just a few colleges, there are lot of colleges which will give admission wit 70-80%. So, don't worry. You will get admission in BA HON. in Kolkata only.

Hope this answer helps.