metro pcs did not honor price quoted at store than proceeded to change price corsicana, Texas

We went in the store to buy a Lg Esteem phone, and asked carlos (the sales rep) how much it was and he said "its on sale for $199.00," so my boy turned to me and said he wanted it, so carlos proceeded to activate the phone and than he said "I made a mistake, its actually $329.00, all total it would of run around $429.00 with aactivation fees too. I called coperate and asked them why they didnt honor the price we were told in the store and they said they didnt have too. So I asked to speak to a manager and they told me to call back to speak to another rep.