BUT they had no data sheet at all. I am clueless how to make it work with arduino. I don t even know where to connect the power for the backlight. Nor do I know how to make it work -> display text with the help of the I2C libraries.
Based on what I could find, this LCD is likely an HD44780 compatible display, but it has an I2C interface in front of that chipset; without a datasheet (I couldn't find anything - a few people asking about it, though), it would be nearly impossible to figure out.
If I were you, I would return it and get your money back - if you can. If not, put the LCD in your box of "get 'round toit" items, and come back in 6 months or a year, and see if anything pops up searching again.
It was retrieved from a completely rusted object, but the screen seems to work. It is a 122x32 graphic screen, labelled "NMTB-S000087FYHSAY-04" and we can see "KL SN102 94V-0", but I didn't find any datasheet. I would like to use u8g2 lib to interface it with an Arduino but the screen is not supported. I didn't manage to find the controller for this display.