Hello @Acheocon,
A bit more information would be helpful as to which phone and what the cost supposed to be and what does the email say.
You should note that when getting a device on promotion at a cheaper rate the actual cost of the phone does not change instead you will receive a bill credit to offset the cost, for example, if a device is normally $20/month but is on promotion for $10/month you will still be billed $20/month but then get a $10/month credit to offset the difference.
