Interest rate not what I was promised

Hi, service not bad up to the point where I found out that the negotiated interest rate is much higher than what I was promised. When they tried to sign me up Ester from sales told me "why do you have to pay interest back? you will only pay the outstanding balance" Well, not the case. I now found out that I am paying interest back up to 12% on some accounts. That to be is absolute BS. Sales will do anything to sign you up and make promises they cant keep to.