door to door price is a lie

Door to door ATT rep sold me an upgrade and ATT retention and billing have no record of the price quote I was given only of the upgrade. It's gone round and round and I feel it's intentional because each time I call there is no record of my last call. I was told a ticket was filed and a case was opened.  No record of it today.  I was told 2 time supervisor would call back and no call.  They are stealing from loyal customers and about to this this one of 20 years.