Should Not Have Been Charged For Carry On.

On April 16 at Logan Airport, Boston, I was charged $45 for checking in my bag.  When boarding I along with several other passengers was taken out of line and told my small carry on was too large and that I needed to pay $100.  I put my bag in the sizing bin upside down and it fit perfectly.  The attendant made me put it in right side up and the collapsable handle was above the line.  I asked for the supervisor who "adjusted the charge" to $50.  This was definitely entrapment.  I expect a refund of this amount and will pursue this further if not satisfied.  Laura Doherty