Fontana Gallery, Inc. Charged 20X what price should have been New York New York

My cousin made her first trip to America from Britain this week.  We took a day trip to NY City yesterday.  She needed batteries for her camera - AAA.   There was a group of us so we just waited outside the store where she went in to get the batteries.  I never imagined they would over charge her 20X what the batteries should have cost.

She was charged 79.98 for 4 AAA Energizer Lithium batteries plus tax.   I am finding them online for $4 for a 2 pack on up to $14.95 for 4 pack.   She paid cash and they did not give her a receipt - she knew it would be a bit more money because it was New York City but had no idea how much they were overcharging.   They made sure she opened the package and put them in her camera before leaving the store also.  So when she came out and told me what they charged her I went back in and told them it was way too much.   They showed me the $39.95 price on one of the 2 packages that they gave her and that she had already opened them so they wouldnt refund me the money.  I did however make them write me a receipt so I had their information to file a complaint.  These people need to be put out of business.  They saw that she was a trusting foreigner and totally took advantage.  I couldnt be more disgusted with her New York City experience.