i have a question, is credit sharing applied in value plus family plan ?

let say the main line is 50 and the sub line is 30,
if main line use only rm15 and sub line use rm60, are they still being charged rm80 or separately?

already 2 months i was charged seperately, whereby i spent less but my bil was almost doubled.

I called 123 five times for clarification but they explained to me only credit limit was shared between the lines, whereas credit sharing was not applicable.

I feel like being cheated, and the call operators are unprofessional, they do not understand well about the service of Maxis.