falexandru:
Could be a genuino BMP280, I dont know. The shop from where I brought usually indicates a brand when it is one and it did not in this case. But indeed, who knows, it might me just an omission.
I don't know if Bosch makes breakout boards - anyway you'd see the brand of the maker of the breakout board, not of the maker of the sensor that's on the board. So that part makes sense to me.
Back to your connection problems: be aware that this is a 3.3V sensor. So you need a 3.3V Arduino (or NodeMCU or so), or you need level shifters, or you need a breakout board that has level shifters and regulator on board (some such breakout boards have this, others don't).
On my NodeMCU I've had no problems with this sensor. Plug & play with the Adafruit library. Do check whether you see the sensor at all, and which address it's at, using an I2C scanner.