Over Booking of flight

Trying to board my flight with my son the gate was closed in front of me. My bags were removed from checking and i was told to report to the ticked office. i was then told to pay additional cost for new tickets as the gate was closed and i missed the check in time. This was a complete **** as i ltr found out flight was over booked! All the Kalula staff were totally unhelpful at Landsera. I am a frequent flyer. This was my 6th flight for the year. After this i will never fly Kalula again and our staff on any company trip! Thank you Mango for your Swift assistance!