Password issue

I purchased macbook pro 2020 with M1 chip in November 2020. I am a Ph.D. Student and spent so much money so that my data is safe. Last night after finishing my work i closed the laptop and on the next day when wanted to log into my laptop, it didnot accept the password with which i had used to log in on the previous day. I don’t understand as to how this has happened overnight as the password wasn’t changed and has been the same since the last 6 months. I then contacted the service centre to help me out, they have no solution because whatever steps they are telling me to follow are not there on my screen. There is no option to reset the password as well or log into my laptop with my apple id. The cost of this problem is that i lose all my data collected over the years with no fault of mine. Is this the quality apple provides to it’s users? I feel so helpless because i have lost all my work with no fault of mine and all of it was done with so much hardwork. Can someone please help me to recover my work?