AT&T Store Houston Beltway 8 And West

I had interactions with three different employees and they were friendly and patient.

Very disappointed with their customer service. I came to activate an old phone (an ATT Samsung flip phone) into a prepaid plan, the store associate Christian told me this was easily done, so they sell me a SIM card, plus paying activation fee and add some credit. I paid immediately. Next, they proceeded to install the card, but when I tried making a test call, the phone never worked.
After an hour with ATT customer service on the phone, I decided to request my money back, as the phone never got service. They refused to reimburse me the SIM card charge (Even if I gave them the SIM card back as it was no good for me).
Later I learnt that this store is not ATT Corporate, but a reseller. They were unwilling to accept their mistake and take responsibility for something very trivial. This is not the way to do business, to make the customer pay for the staff mistake! I tried escalating this issue with the store manager, with no success. Then I called ATT Customer Service, and they sympathized with my situation, but they did not have the authority to intervene as this is an independent reseller.
I strongly advice to go to a real ATT store, where they will actually treat you way differently. In the corporate store, the associate immediately told me the phone was not compatible with any SIM card being an old phone.