I had a look at your design and the datasheet. It looks to me like your design is based on 1.6.2 - VCC generated by internal DC/DC Circuit. If i look at the table 3.2 DC Characteristics, it states that Vbat needs to be 3,5-4,2V. You are only supplying 3,3V. The interfacing examples all use 3,6V for Vbat. So maybe this could be the reason for the display not working.