Monthly Data Rip-off

I have a data contract with Vodacom and am supposed to receive 5G data monthly. I usually log on my laptop for a few hours in one night per month and the entire data gets depleted. I do not download videos and stuff but how does one finish 5G in 2 hours per month? I have another router for 1G and its data lasts much longer than the 5G, how is that possible?

This is a total ******* and i want to cancel the contract asap.