Ah okay, thanks alot. Actually I did hear it spoken. There was a character on CCTV that used it when describing a Chinese saying to the English Character. I was actually unbelievably confused when he said it, because 尚未 seemed like a positive sentence instead of the actual implied negative from the 未 (only because I didn't understand 未). It seems like the consensus is that 尚未 is formal and written much more often. So thanks a lot!

Both "haimei" and "shang wei" could be underestood as" not yet" in meaning. However, like you said, they are used in different settings. "shangwei" is a totally written language, I've not ever SAID it once all my life and I've hardly heard anyone else say "shangwei" either in daily conversations or in business situations. Yet, I do use it in emails, especially in some emails for work. For instance, I'd write" 我尚未收到您的报价“. It seems very formal and professional. And that is why I employ it for working stuffs. While, "haimei" is broadly used and considered appropriate both in formal/informal and speech/writing situations.

没有 means no/not eg：我没有手机 I have no mobile phone 我没有做这件事情 I am not doing this 尚未 only means not yet

两种说法都对。但是第一种更口语化，更现代化。第二种，说起来有点像古人说的一样。如果要说的话，还是选择第一种更好。【By the way,I want to make friend with you...:)

尚未=还没=not yet 没有=not