Stop and Shop complaint: Unresolved Visa Credit card issue

I purchased a Visa card for $50.00 on May 5th at the Stop Shop on Station Ave in South Yarmouth MA. It was a gift for my Granddaughter, which I gave her on May 6th for her birthday. She tried to make a purchase with the card and it wouldn’t work. Her father tried to help her and he couldn’t get it to work either.
I returned the Visa card along with the activation slip and my receipt to the Customer service desk at the Station Ave store on my way home. The Customer Service Associate called the Asst Mgr., Kevin. He said he had to investigate whether the card had been used and would call me. I called back today and was told that he is on vacation. Today is May 11th and I have no resolution as to this problem. I told my Granddaughter that I would bring her a new card that would work a.s.a.p. I am really upset that the Assistant did not resolve this before going on vacation. My name is Patricia MacConnell, 26 Tall Pines Dr., Yarmouth Port, MA. My phone 508-505-7419 (cell) 508-619-7119 (home). I would like to get an answer regarding this problem. Thank you