4G dongle data usage Rpi for ESPEasy

[NetEye]

Dear,
Can somebody tell me how I can reduce the usage of 4G data on the RPi running Domoticz.
For test purpose I disconnected all the sensors (RPi running single) and still the 4G dongle is using a lot Mb’s (around 1000mb a day).
For the connection with the world wide web I use a 3G connection on a wifi modem.
When I disconnect the RPi from the modem, also the data cunsumption is zero.
Therefor I point to the RPi with Domoticz as suspect.
For instance I found out that watchdog is using data so that I need to stop.
I stopt the auto update of Domoticz also.
What can I change or stop to reduce the data usage to around zero.
Regards