Telkom Mobile *****s data (Data just disappear)

I have a contract with Telkom Mobile. I receive 10 Gb every month. The issue here is my data just disappears. I tried to call Telkom and also went to their shops to report this and I am not getting any help. Telkom claims that as long as the router is on it will drain my data, but this is nonsense because I have another router with a different network which I leave on 24 hours seven days but the data doesn't disappear like in Telkom mobile. To me Telkom Mobile are ******* who claim to be the best broadband company in the country, but I disagree, they ***** our data. How can data disappear because a router is just on. Even if it would take some data, not gigabytes of data. Telkom Mobile data contracts are a ripoff and I will definitely cancel it. The issue is they want to talk about cancellation charges even though they are the one who are not fair in this agreement.