How to pay the visa transaction cost? (Santiago de Chile)

Hey everyone
I went down to the office to extend my turist visa yesterday and was told that all I had to do was pay the bill of Protected content
I believe the woman said that I could do it in whatever bank, but that sounds a bit strange to me. So my question is - where do I go to pay it?

Also, I was a bit confused to see that they didn't give me any stamps and even took my tarjeta de turista. This means that after I pay the cost I won't have any proof of the visa renewal.. I really don't want any problems in the airport when I leave..
Do I need to go down there again to obtain something?

Thanks!