Changing institutions is a federal matter and you have to update the same with CIC. Here is the link
https://www.canada.ca/en/immigration-refugees-citizenship/services/study-canada/change-schools/account.html. Do note you need to have a confirmed offer in the college you want to join before you can do this.
Getting refund depends on the refund policy of your college/university. While the refund policy differs, expect to pay up to 500 CAD to 1000CAD as refund fees, if not more. Some many not allow you take refunds, or their policies are opaque, as some students of ISI Montreal found out this year.
I just wanted to know, why do you want to change your college/university? Surely you must have done your research in your home country first before joining?