Excessive data usage on mobile - no attachments

I have the latest version of eMclient according to Play Store, on Android 16.
I am roaming, so mindful of data usage.

However, eMclient managed to consume 8GB (Gigabytes) of data in the last 3 days!!!
Please note that I only have 2 email addresses, and that the messages for both are setup for message download only WITHOUT the attachments.
I received 100-200 emails in that time-frame, but absolutely nothing that would justify 8GB of data transfer.

This happened last month as well, and was about 10GB in 1 week.
I dismissed it then as a freak glitch, but not twice.

Has anybody experienced this issue?

No pise, ze se mu to deje uz druhej mesic. To mimochodem znamena, ze to asi uplne nebude hybrid syncem.