Unable to use gift cards bought from target, Best Buy

I have bought 5 Apple gift cards online from target, Best Buy and Amazon. I was successful to load into my Apple Card balance but when trying to use them to buy an iPhone, I’m getting transaction failed use different card… when tried to buy instore… it shows some unusual activity and transaction not approved. Even store employees unable to figure out the issue. Called customer service and asked them to refund back to gift cards, they did and tried applying gift card pins in the transaction…still no luck…. Finally I want to understand why I’m unable to use the gift cards or Apple Card balance even after redeeming into my Account? Are best buy and target a scam to buy gift cards from?