Clips to release seat

I recently bought a 2nd hand Bugaboo stroller that was purchased in 2014. I think its one of the Cameleons. Already, the push & slide buttons on the sides are not working and I’ve had to dismantle both clips to remove the seat. I dont understand why it isn’t releasing and I’m unable to collapse the stroller to carry in the car since I got it home and assembled it. Any suggestions would be appreciated.