I was never able to find fresh cranberries in BA. I had to bring them from the US. It is not difficult to reconstitute the dehydrated cranberries, however. One of the years I brought cranberry sauce to your place, I made it with reconstituted dried cranberries and nobody knew the difference!
The weird thing is that Argentina is a large grower and exporter of cranberries! Sometimes when I buy fresh cranberries in the US, they say product of Argentina.