A Unusual experience of CN Tower

Yesterday, we went to visit CN Tower in the morning. we arrived at entrance at 9:45 and waited for our classmates. after taking a group photos, We came into ticket office and lined up at the ticket counter for checking in. But after the staff checked  our ticket, security guard rejected us to visit CN Tower because they thought our ticket that purchased online is invalid due to agent which sold tickets to my teacher. Our teacher discussed  the matter with the staff. we had to waiting at  ticket office for a long time. but at last they still insisted on their opinion. If we want visit CN tower ,we must make up price difference, It is about $20. It is unacceptable for us. It is very disappointed for us. teacher apologized to us and promised refunding ticket fee to us. He said we had to cancelled visiting CN Tower, but we can visit other places. When My teacher had to stay there and handle the matter. we left from CN tower and visited steam Whistle Brewery and Railway museum.  first ,Then we go to Harbourfront centre. walking beside lake and breathing fresh air is a delight for me.