If it's beyond 24 hours, I would want to examine the fare rules before calling. Agents can be wrong and can decide to just make up stuff to end the call quickly.
BTW, how big was the fare drop?
Also, if it's ten tickets, these probably were booked as a group (9 is the max on a normal PNR), which would further complicate the situation. In fact, you can't even see fare class availability for more than 9 tickets.
Did you use a travel agent or OLTA?