Proration not calculated fairly

Got the 100gb (50Gb double data) deal on the 16th of December. They only gave me 25GB prorated. Half the month should be half the data surely.

Spent 30 minutes on the phone and they didnt want to tell me how much was loaded. Couldnt even get how the prorata works. Only kept telling me how much I already used (21gb) and that he must wait for the system to refresh to know if i didnt spend the rest in the last day or so. Ridiculous. Told me to go in store.

Waited 1hour in store to be helped. Only 2 staff on duty. She told me 27GB was loaded and said i whoukd have had 4 bundles loaded for the double data deal not 2. Couldnt add the missing bundles in store and logged a ticket. So i wait.