MTN contract sim data depleted in rapid time.

Took out 2 X 30gb Sim cards from MTN. It was delivered on the 5th of July 2024. The data runs out so so fast. Sim 1 -30gb gone 3 days. Sim 2- 11gb used in one day. Routers are switched off as soon as we get home. Before the contracts I bought a 6gb weekly data bundle and it lasted me a whole week with some of the data expiring due not being depleted. So how can the contract sims data run out so quickly... I called MTN to cancel as I'm still in my cooling off period. Thank you, Dillon, for assisting me with the cancellation. Now to wait and see if anything will be deducted from my account month end