"I will say this, if I find out that Citibank has charged my card twice or even if they can show a hit for the transaction I will offer my thoughts to Sobey's"

If it turns out you were charged twice, it will means the first charge went through as you had thought, bolstered by fact that the pump proceeded to dispense fuel. It has been my experience all over the lower 48 that you will stand there and wait some amount of time (if it's a dial-up system) until it is authorized. In that event, it isn't a 'misunderstanding', it was brain fade at best and incompetence otherwise. Re-training of the clerk, and an apology from the establishment would seem in order. That's my last two cents on this one. Thanks for listening.