It’s not unusual to have brokerage firms or individuals contracted out by the larger companies to assist in manners like this. Who was your original Lessee? It may be worth contacting who you originally leased with to confirm what’s going on.
Look in the Fisher County deed records to see if there is a recorded assignment into Cholla and if your lease is listed in the Exhibit. Or ask the landman for a copy of the recorded assignment. Leases are often assigned over the years and you will not be notified unless your lease requires notice.