told me to send them another BTC from the address that I used then
I bet most exchanges or related services do the same thing, except if the user provided KYC already for verification.
On the other hand, either what's the price of
BTC 3 years ago, 3
BTC is still huge amount and it's really frustrating if the amount cannot be refunded. The changing of terms is really off and I feel like there's nothing you can do about it, else if you take legal procedures about it.
BTW there are lots of scam accusation of changenow.io
this one if the latest I guess, and using the exchange is really a risk.
It wasn't KYC, I just didn't notice this transaction, but when I remembered, the ID was lost, as it seemed to me then, as was the hash leading to them. They just kept it for themselves.