bad customer care

i bought a five pair os socks pack for my son on the 15 Mar at MrP Woomead retail park, when we opened them the next day, one sock had a big hole on. I tried to contact them on *** and *** with no response since Wed til today. I phoned the customer care nr, spoke to a lady, i explained the reason for my call, she said she was putting me through the branch, i was on hold for more than 15 min, then when the other lady responded , she said they actually put me through sheetstreet and she doesn't have numbers for MRP store, i tried calling back then the center was closed, meaning that person was in a hurry to drop the call so thy can knock off but what about my query that I have been trying to get hold of her store since wed? Where is the customer care there. All i need to know is can i bring that 1 pair for exchange at same branch or i can do it at any branch, can someone revert to me