I'm not sure how payment charge works so perhaps a TA can explain this to us. However, my experience is that most TA will forward your CC# with the ticket purchase and the charge eventually comes in from the airlines directly, with the ticket# printed on the credit card transaction. I also noticed that some TAs charge the credit card right away in their office. The payment control centre (or whatever this is called) at the airline probably does not know about this, then will charge again when the transaction is received/reviewed.

Ticket number is very important here. You need to prove that both transactions were charged for the same number.

Unforunately, CIBC VISA is not very helpful to deal with customer dispute. I once lost close to $100 in interest because my electronic payment was "lost" between the chequing account departure and visa centre receiver. It eventually showed up 5 weeks later... my bank said that it was CIBC holding the money and delaying the payment. The tranaction date was dated the time I paid, but the posting date was 5 weeks later. Still CIBC kept blaming my cheqing account and refused to issue refund for interest. I was stuck in the middle... could not argue with two big banks. The amount was too small even for small claim court... so I had to absorb that loss.

Anyway, my point is... good luck. You probably need it, in addition to lots of time available to make calls and write letters, to see that money again.