I don't see it as a mistake, I see it as a (good!) test.
I think that nowadays every website can and should make both www. and simple urls work.
And probably this can help OP fix that.
thanks for this, I changed the DNS records, it should be ok now with the www link.
I would suggest creating your own domain, because not only is it unethical but could lead to trademark problems in the future.
I doubt owner of preev.com registered term "preev" as trademark/intellectual property which associated with Bitcoin/crypcurrency exchange rate. I can understand your ethical concern though.
While waiting, you could use different website or your search engine (by typing "X btc to [preferable fiat]").
It's not about registering the trademark, it's about intent.
The original owner created the brand Preev for their price exchange app. If another person registers the same domain to profit off another's brand that may confuse consumers, then that is illegal in a lot of places.
preev.net will not be a commercial site. there will not be any illegal actions, nor will it serve to provide any information that may mislead users. only informative, where users will get information about the current value of certain currencies in the easiest way. it will have the same function as the well-known preev.com site, which has a problem being online, with some additional possibilities.