Zenner Water Meter "Problems"

Hi all, I encounter some issues with the Zenner Water Meter and I wonder if you have a clue about how to fix this.

I received data once per day, here is a payload “ESgAAAA=”.

Based from the documentation, a daily scenario means that I should receive a payload with two packets
image

A guy from zenner gave me the documentation to understand packets, but I’m stuck…
"SP1
Content packet type 0x01, 0.5 no of bytes
subpacket type – 0.5 no of bytes
day value 4 no of bytes

13 no of bytes overhead
18 no of bytes total"

"SP9.1
packet type: 0x09, 0.5 no of bytes
subpacket: 0x01, 0.5 no of bytes
timestamp, 4 no of bytes
status, 2 no of bytes
reserved, 4 no of bytes

13 no of bytes overhead
24 no of bytes total"

Do you have some idea ?
Regards