as the others have mentioned, the agent was wrong (although it is a change, but was changed about a year ago). Te refund is not always automatic but has been for many
if you need to call, quote from
united.com
However, for travel which includes segments in United BusinessFirst or United Global First, miles and co-pay will be re-deposited if all the United BusinessFirst or United Global First segments could not be upgraded. When applicable, these refunds will occur automatically 7 to 10 days after the trip.