Avocados don't ripen? Slow to turn dark and they stay hard

My are Shoprite stores having been selling avocados every week for only $.89/ea so I've been buying a number of them. I've left some in a bowl with other fruits like bananas, apples and tomatoes and others I deposit in the fridge to ripen later.

None of the avocados on the counter have ripened and these ones are two weeks old. The skin turns dark but they stay rock hard. Normally it would take 2-5 days average to get them buttery soft in the summer but these ones don't seem to ripen. I already opened two to make guacamole, a little rotten on the stem end but the rest was ok, just hard and not ripened with softer parts here and there. The skins of these avocados are thicker than normal and they don't thin out over time.