Erratic Price Quoting

First I get a email that tells me my promo price is ending, then I talk to an agent online that quotes me 35, then I get an email that states it is going to be locked at 57, then I get another agent that quotes me 65 (which would be higher than the default contract) and then I get a guy on the phone who can do 39.   Whyu doesnt Xfinity just set prices and stop playing these games with thier customers?  This cannot be helping an already infamously low customer service rating.