nikos,

with some changes to your code you can still save sereral hundred words of codespace.
(Less than 1200 words should be possible)

Store the "static" strings in EEPROM

Do a search for "STRINGS EEPROM" and you'll find many examples.

Reduce the number of I2CWRITE statements by writing a subroutine "I2COUT"
Stet the required parameters and call that sub.