Since there are more shoe stores in BsAs than practically any business but lingerie stores, I have to wonder- do you walk the streets with your eyes shut?
Try-
Any Mall.
Every 4 feet along Calle Florida.
Every other store on Santa Fe.
All over Palermo Soho
twice a block on every commercial street within General Paz...
You can buy real converse, in plain, classic styles, or in leopard skin, black leather, gold lame, and so on.
Or Brazilian knockoffs, or, even cheaper, chinese knockoffs.
Every neighborhood shoe store has a few knockoff designs, for not much at all.
Buenos Aires is shoe central. Nowhere else in the world can you find the variety, at such low prices.
If it was me, I would hold out for a pair of Carpincho converse style hightops. Never seen em, but they must exist somewhere.