sorry to here about your loss.
the only thing that strikes me is your basking temp. for a baby it needed to be higher. around 115 degrees. nutrabol twice a week and pure calcium dust 5 days from seven.only dust one feed per day but babies need a minimum or 2 live feeds per day.
i would definitly go back to the shop although they probably won't admit that they have a problem if you know what i mean. and don't speak quietly either if they are funny about it.