Forced into upgrade just to make a sale

i had an upgrade due and wanted to wait for the right time to do it. when the agent phoned me he assured me that i can update my line and add a phone at anytime. when i wanted to add the phone i was informed i cannot because the upgrade is done already. its unacceptable as now that i need a phone i cannot add it. after 15years as a client this is the service i receive which is totally unacceptable,