I just joined the group and read your message posted about a week ago. I hope by now your new baby is adjusting to his/her new home and eating properly.
It's an all new world to babies when they go to new homes. In order to make the transition more comfortable, pick out a place beforehand where the cage can be in a centrally located area of the house, but yet next to a wall or corner so they don't feel they have to be "on guard" for something sneaking up on them. Cover top and 3 sides of the cage, leaving front exposed, for the first couple of days. That way you can sit at a non-threatening distance to watch and make sure they're eating and drinking.
Since birds don't like to go down to the bottom of the cage at first because they fear predators, clip healthy foods to side of cage, just above their highest perch. This can be broccoli, spinach, grain bread, millet spray, etc.
Sometimes recently-weaned babies revert back to wanting to be handfed. If baby isn't eating within a few hours, contact the handfeeder to see if you can supplement feed (Exact handfeeding formula mixed according to directions on package, making sure it is right consistency and correct temperature, fed with a crimped spoon)or return the baby to the handfeeder for a few days. Since cockatiels are such small birds with high motabolism, they need to eat often.
I prefer to advise 'others' who aren't experienced in handfeeding to use a spoon with crimped sides (to simulate a beak), instead of syringe, because feeding has to take place when head is bobbing which shuts off airway to prevent aspiration. Sometimes those not experienced in handfeeding will try using the syringe, force the food, and strangulate the baby. Food can't be forced, but instead let the baby get a taste of the formula from the spoon, and then it'll grab hold, bob it's head while eating.
Please let us know how your baby is doing. 
