I am experiencing data that, all of a sudden, lasts 15 days.

I have an over 3 years contract with vodacom for data, which is 100 gigs night and 100 gigs day. My family and i were using this data during Covid_19 for work and personal purposes, and i had never ran out of data. All of a sudden, without changing anything in our lives, except that this data is only being used by my daughter and i, i run out of data within 15 days. This is the 3rd month i am experiencing this strange behaviour with my vodacom data. Last most when i enquired i was advised to switch off background app refresh, which i did. But for strange reasons, i have run out of data, 15 days after the data was loaded. I would like for Vodacom to explain what is happening with my data now, before i terminate my contract with them and find a SP that will not play with my data.