Excessive / incorrect data usage

I currently have a monthly 20GB data allocation. Most of the months the 20GB is fully used, which is very strange since I expect the usage to be around 2 GB at the most, my reasoning: -originally I had 1 GB which were enough for 4 persons using cellphones and 2 laptops. -Telkom increased my allocation to 2GB and somehow it ended again close to the 2 GB for the month?! -I change to a new deal for 10GB and somehow it ended then close to 10GB?! -Telkom increased my allocation to 20GB and somehow it ended again close to the 20GB? we are now 3 persons.

It was confirmed that all the usage is from my telephone line. I requested numerous times a log of the data usage to be able to verify the usage count, but without success. My theory is that the counting is inflated.