Walmart complaint: Trying to get a refund

I went to Walmart to buy a I Tunes Gift Card. I don’t know anything about gift cards. I did not see the I Tunes gift cards. So I asked a cashier to help me. I asked the cashier if they sold I Tunes Gift Cards. The cashier said yes and came back with a Google Play Gift Card. I asked the cashier if
that is the right gift card. She said yes. So I purchased the google Play Card and asked the cashier to load $200 onto the Google Play Gift Card.
All the while thinking that it was an I Tunes Gift Card. So the next day when
the Gift Card was being used for a payment. The Google Play Gift Card could not be redeemed for the payment. So I went back to Walmart for a
refund. I was told that the Gift Card is not refundable. So I told Walmart that the cashier who sold me the Gift Card did not tell me that at the time
of the sale. Walmart told me that they can’t do anything to help me. They told me that I had to contact Google Play to try and see if they will give me a refund.

I have been trying for the 3 days now to get a refund. from either Walmart or Google Play. No response from either company.