If your data is not structured and can be just a plain “text file”, then maybe you can consider the AT commands to write (+UDWNFILE) and read (AT+URDFILE) files.
Use the sample sketch (hologram_dash_passthrough) sample code to execute AT commands via Arduino Serial Monitor.
Here’s the site where sample code can be seen (under HTTP POST sample). Disregard the APN setup and other commands.
Link: UBlox AT commands sample code
See full documentation here for File System (page 494) usage.
Link: UBLOX AT Commands