brother to be sure before i posted i looked for hadith and i found these: From Asma bint Yazid she referes that the Prophet

said that the secret name of allah is found in these 2 verses: Baqara,163 and ayat al kursi in the beginning and guess what! The same exact pharsing that i've been told in the dream is said, moreover it doesn't go against our aqeedah 'cause it's not EXTRA REVALED KNOWLEDGE but a knowledge that was already there in another hadith even Sa'd ibn Malik reported that the Prophet

asked the sahaba:'' do you want me to tell you the secret name of Allah that when supplicated Allah answers His servant? they said Yes and the Prophet

said that it is the invocation of Yunus

from the belly'' and again the phrasing of that du'a is very similiar, and again in another hadith from Burayda the Prophet

heard a man do the du'a by saying that phrasing and when the Prophet

heard that he said '' by The One in Whose hands is my soul, this man invoked Allah with his secret name and therefore Allah answers the invokation and satisfies the du'a.
This and many other incidents like me doing istikhara in the past regarding this same matter and other proves the opposite of what you said and actually before you say a categorical no it would eb better to look for proofs

! i gave you qwhat i have and nowhere in the WHOLE islamic teachings it is said that we people cannot know of this name(i'm actually not sure tho if this is A PART OF THAT SPECIAL NAME or all of it, but i can tell you that i believe it surely is tru, and even more i etsted it eheh so what better proof than the test itself?)
and may Allah guid me and all the believers and perfect our religion and the practice of it, AND ALLAH KNOWS BEST
wa jazkaAllah for your answer, and again share atleast the du'a by saying that ''it is a good way of calling Allah'' if you personally don't like it for noone has to believe that IT IS THAT NAME but in the same time, i don't see anything haram in calling Allah by telling Him ''there is no god but Him'' in the du'a SO ATLEAST USE IT,SHARE IT and peace be upon you and the love of Allah and the pleasing of Him be upon you my dear and respected brother
