Postage to Brazil

I just wanted to know peoples thought on this scenario or their experiences about postage to Brazil.

I've seen in other peoples listing in the past that Brazil is a country that they will not post  to.

I've recently had a buyer purchase an item that is making me feel a  little uneasy and lean toward not wanting to post it to them in Brazil either.

I recently sold an item to a buyer, the buyer paid approx $50 for the item, I quoted them $68 for postage as that is what the result on the postage calculator was. They paid the invoice I sent with these amounts straight away.

I then went to post the item to them but the PO said that postage would be $90. I then went back and messaged the buyer to see if they would like to pay the difference, and they said they would.

I'm just feeling a little uneasy about this and worried because they are paying twice the amount for postage than what the item is worth. I know if that's what they want to pay then that's up to them, I'm just a little worried that this is going to come back and bite me, so to speak.