Hello.
i am sorry, but there is no way to send them faster, each data packet has a limit. Quote from our Wiki
Note: for FMB630, FMB640 and FM63XY, minimum AVL packet size is 45 bytes (all IO elements disabled). Maximum AVL packet size is 255 bytes. For other devices, the minimum AVL packet size is 45 bytes (all IO elements disabled). Maximum AVL packet size is 1280 bytes.
Device packs as much data as it can in one packet and then sends it, so if you have many records generated it will take time to send them all to server as device can store big amounts of records in its flash memory.
Maybe you can adjust Data acquisition setting to generate records not as frequently so there would be not as many records to send if devices goes offline for a while.
Best Regards