Please let us know which display you are using. Check if the display has support for 2 bits per pixel (bpp). If you are using the display that comes with the CY8CKIT-028-EPD Shield, then note that using 4 grayscales (which is 2bpp) won't work since the display only supports 1bpp.
You can find this information in the datasheet in the section "Writing to Memory" here.
Attach the datasheet of your display for further help.
I had a look at the link you attached for the display you are using. Looks like the display is compatible only with the HULK evaluation kit and the Firmware programmer (MSP-EXP430G2) which is provided with the kit to load images on to the display.
When interfacing any display there are a number of steps that need to be followed for initialization and these steps are mentioned in the datasheet of the display driver. But I see only a quick start guide kind of documen available which uses the HULK eval kit and the Firmware programmer (MSP-EXP430G2) software.
I'm not sure where to look for it, please check with the display manufacturer. Once you find the initialization sequence for the display, please send those values using the SPI during the LCD Init. For example, in the code example CE223727, you will find the file "pervasive_eink_hardware_driver.c" where there is a function Pv_EINK_InitDriver(void) which does the initialization. You need to modify this file with your sequence.
Hope this helps. Let me know if you have any further queries.