@Sunseeker According to the Connecting the Radio page, D2 is the default pin for the CE signal for the NRF24. If you'd like to use this pin for I2C, you can free it up by assigning a different pin for the CE signal by adding this line to your sketch:
#define MY_RF24_CE_PIN pin
IIRC, all available pins should work for this purpose (D0, D3, D4). Just pick one and if it doesn't work, use one of the other pins. Please make sure to add that line before #include <MySensors.h>.
