I'd guess it was expended availability. You should give the agent your FF #.
I did and they claimed they logged on to my account and could not find it. Something is fishy. This is what shows on my screen.
2 Award 90,000 miles
Additional taxes/fees $22.40
Total Price 90,000 Miles and $22.40
Want to save your miles? Consider one of these options.
Purchase this Reservation in Economy for $2,096.34 without redeeming miles
Purchase
Purchase this Reservation in First/Business Class for $3,962.56 without redeeming miles
Purchase
Flight Details
Mon., Jul. 27, 2015 | New York, NY (LGA - LaGuardia) to Maui, HI (OGG)
Depart:
7:05 a.m.
Mon., Jul. 27, 2015
New York, NY (LGA - LaGuardia)
Arrive:
8:34 a.m.
Mon., Jul. 27, 2015
Chicago, IL (ORD - O'Hare)
Flight Time:
2 hr 29 mn
Flight: UA1604
Aircraft: Boeing 737-700
Fare Class: United Economy (XN)
Meal: Food and Beverages for Purchase
No Special Meal Offered.
Change Planes. Connect time in Chicago, IL (ORD - O'Hare) is 56 minutes.
Depart:
9:30 a.m.
Mon., Jul. 27, 2015
Chicago, IL (ORD - O'Hare)
Arrive:
1:25 p.m.
Mon., Jul. 27, 2015
Maui, HI (OGG)
Flight Time:
8 hr 55 mn
Travel Time:
12 hr 20 mn
Flight: UA202
Aircraft: Boeing 777-200
Fare Class: United Economy (XN)
Meal: Food for Purchase
No Special Meal Offered.
Tue., Aug. 4, 2015 | Maui, HI (OGG) to New York, NY (LGA - LaGuardia)
Depart:
9:25 p.m.
Tue., Aug. 4, 2015
Maui, HI (OGG)
Arrive:
5:08 a.m. +1 Day
Wed., Aug. 5, 2015
San Francisco, CA (SFO)
Flight Time:
4 hr 43 mn
Flight: UA1557
Aircraft: Boeing 757-300
Fare Class: United Economy (XN)
Meal: Food and Beverages for Purchase
No Special Meal Offered.
Change Planes. Connect time in San Francisco, CA (SFO) is 42 minutes.
Depart:
5:50 a.m.
Wed., Aug. 5, 2015
San Francisco, CA (SFO)
Arrive:
11:54 a.m.
Wed., Aug. 5, 2015
Chicago, IL (ORD - O'Hare)
Flight Time:
4 hr 4 mn
Flight: UA734
Aircraft: Boeing 757-200
Fare Class: United Economy (XN)
Meal: Food for Purchase
No Special Meal Offered.
Change Planes. Connect time in Chicago, IL (ORD - O'Hare) is 1 hour 6 minutes.
Depart:
1:00 p.m.
Wed., Aug. 5, 2015
Chicago, IL (ORD - O'Hare)
Arrive:
4:16 p.m.
Wed., Aug. 5, 2015
New York, NY (LGA - LaGuardia)
Flight Time:
2 hr 16 mn
Travel Time:
12 hr 51 mn
Flight: UA2048
Aircraft: Airbus A320
Fare Class: United Economy (XN)
Meal: Food and Bever