A FlyerTalk Posting Legend
Join Date: Sep 2009
Location: Minneapolis: DL DM charter 2.3MM
Programs: A3*Gold, SPG Plat, HyattDiamond, MarriottPP, LHW exAccess, ICI, Raffles Amb, NW PE MM, TWA Gold MM
Posts: 100,399
This sounds like travel on Virgin to Australia. Low is 150,000 miles RT. IMO if DL refused to place you in business class for 150,000 miles or refused to let you change without a fee to business class at 150,000 miles for another date on which business class award seats are available, then I think there would be grounds for complaint.
If you think of this like a mistake fare, your ticket was never issued in business for 100,000 miles. Mistake fares aren't considered to be a contract until the ticket is issued. In such cases, the passenger is issued a refund (without a fee) if a credit card has already been charged.