Take some cuttings quick! Before they die altogether. Impatiens start easily from cuttings, and I think you need to start some new plants as backup. You really need to use potting mix for potted plants. Other garden soil products just compact and don't allow enough air to the roots.
They do look like they've dried out to me, too. Heft the pots and see if they feel light-ish. If so, slide one out of its pot and see if the soil is dried into a 'brick' that doesn't absorb water. Then sit each of them in a bucket of warm water (or all of them in the sink) until they've soaked up enough water to moisten all the soil in the pot. If the plants perk up again, get rid of that soil mix and pot them into some fresh, sterile potting mix. (well moistened beforehand)