Hi sorry this happened - most likely it is owned by a park.io user and they can set the price to whatever they want. Feel free to reach out support@park.io and I will see if I can help
Since you're here, maybe you could help us all understand your business better?
1. You are not getting .io names at a discount from nic.io?
No insider deals/information?
2. The Only advantage you have at acquiring an expired domain names at nic.io is your propriatiatry program. A program that is just faster at buying these expiring domains--just faster than your competition?
3. You only know when a .io domain name is due to expire is by looking at the same WHOSIS info we look at?
4. I ask these questions because so many of these domain buying services are just to magical. We tend assume the worst.
I'm guessing it works like stock market bids from high-frequency traders?
They've bought up the closest server they can to the bid receiving server at the registrar and/or they send their purchase request before the domain becomes available -- accounting for the network latency -- so that their bid gets there at the exact millisecond that the domain drops.
My personal domain drops at 2018-0X-0YT00:00:00Z, then IIRC it takes 75 days for it to be cleared. So presumably if your request for that domain arrives at 1 microsecond after midnight on that date then you "win" it.