In all honesty, I am not 100% these frogs will make it. Unfortunately when you purchased them, you were not told how to properly care for them (Something the pet stores are known for being neglectful about)
You bought them in a new gimmick item - a tiny "habitat" which is about 2-3 cups of water at best.
With a heater, better water quality, and a more nutritional diet you may see a HUGE improvement in them.
If unfortunately the changes have come too late, I would not be discouraged from keeping them again. You are on the right track now to learning how to properly keep them and if the changes are made you will know that you have done all you can do