Stop giving cards when I don't need them

I don't know why people insist on giving you something when you've already said no.

A lady comes in with a script for Pariet and Rulide. 

She: Do you need my cards?

Me: No need, your medicare and concession card details are already on the computer.

Guess what. She fumbles around in her handbag looking for the cards. 

By this time I've already dispensed the first item. 

She hands me her concession card.

She: Here you go, you might need this.

Me: No I already said your details are on the system.

She: But you don't have my concession card.

Me: I do.......

She: Are you sure? 

By this time I've already finished dispensing both items. And she's still going on and on about her cards.

Efficiency! If I said I don't need it and its on the system already, that's means I don't need it! If I'm not sure, I would say.