Actually, the CSR is likely correct. You have a few options when the price drops:

If your ticket was purchased today or yesterday:
-Cancel the ticket using the Customer First Policy which gives you a full refund to your method of payment;
-Purchase the new ticket immediately at the fare that is quoted.

This method ensures you lose no money but is only available if the ticket was purchased today or yesterday. (Today = the current day, not meaning 1/25/08).

If your ticket was purchased before 12:01am yesterday:
-You have to use the "Guaranteed Day Of Purchase" fare rule which allows you to refund the difference in air fare for the same flights. This rule charges a $50 admin fee and the resulting difference in air fare (less the $50) is given back to you as a voucher which can then be applied towards future travel.
-Cancel the ticket if it's fully refundable and then purchase the new ticket. The fully refundable fare will be put back on your original method of payment.

So, you didn't tell us when your ticket was bought but those are your options. The initial agent you spoke to gave you bad information if your ticket was purchased before "yesterday".

-RM