That's a shock, one of the perks of being Platinum! I thought they would be simply bump someone according to the T&Cs -
https://www.etihadguest.com/en/our-p...ers_and_Status
Did you meet the requirements in Notes 4 & 5? Maybe your intended ticket wasn't the full Y fare?
- Applicable to guests that are travelling on all Etihad Airways operated flights. Excluding discounted tickets.
- Bookable in the highest Economy and Business class fare (Corporate fares or Abu Dhabi Government Employees Travel Programme discounts are not allowed). Multi-flyer tickets are not eligible for this benefit.
I would check with EY Platinum Guest team -
[email protected] - rather than Twitter team.