Who told you this?  Did you learn this at the Verizon Store?  Because this is the ignorance that is driving this racket and will end up being the death of them. 

This is a bait and switch scam.  It's something the FTC and City Attorney's office will be all over, once they are made aware of it.    I have a witness that worked at the Verizon Store whom left because of this dishonesty.  She was smart enough to know that they were wrong.  The problem is at the store management level.  They are sadly misinformed as to contract law and the FTC laws protecting consumers from what they are doing.    The violation of Business and Professional Code 17500, 17505 and Civil Code 1770 not only nulls the contract, it also opens the door for legal action and potential jail time and fines.  

As a salesperson, what you say to the customer has to jive with what the contract states.  You cannot use subterfuge and misleading statements to get a customer to sign a contract.  The fact that the contract was signed is meaningless from a legal standpoint.  Yes, the store can enforce it, but if you get an attorney and/or the FTC and City Attorney involves the the truth will be painfully bestowed upon the store.