Is Data add on usage used before Monthly data?

Hi,

I purchased 1gb extra data this month as I thought my usage would be higher. I normally have 1gb per month as part of my plan.

However I didn’t need it as I ended up only using 950mb. The add on has just run out and I was anticipating having 1gb left but it looks like my normal monthly allowance was used in priority. Rather than 1gb I have 50mb left.

Is this correct?

i feel cheated out of 1gb.

thsnks

Stupiddougal