What pins to use for I2C bus with AVR Mega2560

CrossRoads:
This is a case of knowing enough to be dangerous 8)

I think OP (original poster) should have just admitted a clear mistake and moved on, but instead tried to find some things to blame.
the fact that the question was even asked tells us the level of knowledge the OP has, and people here are helpful and responded instead f ignoring the question.