Why would you need a voucher when they offered you replacement product?

I bought 2 bags of brown rice from Coles Noble Park a few months ago and kept the bags of brown rice are kept in a big tub of white rice.

Today I went to use some of the brown rice (half used) and noticed that there was a live maggot hanging from the bag (on the outside). I checked the white rice in the tub and noticed that there were little moths inside. I threw out the half open bag of brown rice and got the unopened bag and noticed that this one had about 3 moths and large maggots moving around inside of it.

As the source of the maggots and moths was clearly the bag of brown rice, I went into the Coles from which I had purchased the rice from to ask for a refund for the two bags of brown rice and the tub of white rice (25K worth) that I would now have to throw out.

The store manager apologised and agreed to refund the two bags of brown rice but said that he did not have 25K's of white rice. He advised that I could take a bag of white rice but offered no other resolution. I declined this offer and told him that I only wanted to be compensated for what I lost - nothing more and certainly nothing less. I advised that I could take a couple of 10K bags of white rice and went back to his office.

I then collected 2 bags of brown rice and 1 bag of 10K white rice as there was only one 10K bag of the type that was close to what I had. I took them to the counter and the girl who had been left to deal with me looked confused and said she was only aware of refunding 2 bags of brown rice. She went to the manager's office to check and another person came out - his name was Phil.

He asked about the situation and I said that I wanted a voucher - to which he cut me off and said abruptly - you're not getting a voucher. I explained once again that I only wanted to be compensated for what I lost and said that the manager had told me that they didn't have 25K's of white rice and there certainly wasn't on the shelves when I checked so I would like a voucher for the difference to purchase the remaining bag of rice another time. He then went somewhere and came back with another 10K bag of the same white rice and slapped it on the table and said again, here - you're not getting a voucher.

I found this to be extremely hurtful, that I was being treated like some kind of opportunist when I had not asked for anything more than what I had lost. I had not even asked to be compensated somehow for the fact that I may have consumed maggots from the first bag.

Most likely the maggots came from your house. Also not giving in to you is not the same as being rude.