None of these comments are fixing issues or trying to make a difference. Sending the product back is a really good idea, especially if this change in terms means you can get a refund even if you've had it a long time.
No one can stop you being mad. No one's saying it's not allowed. It's possible someone is still young enough to misinterpret adult interactions as parental fiat, but it's not the case.
That isn't trying to make a difference? Excuse me? Read that back.
You can claim detrimental reliance though, but it's a stretch and bad faith imo. Try your luck with a judge and attorney fees