Bought New Apple TV - But told not eligible for free 3 month subscription

I upgraded the AppleTV to 4K - but chat support said if you have redeemed apple tv in the past for a device, you cannot get a free subscription again using the same ID. No matter how many devices you buy in the future.

Is that true - and if so - why are these terms hidden?

The Apple TV promotion was redeemed by a member of you family sharing group and shared with you. Which would make the Apple ID no longer eligible for another trial promotion.

Thanks.