Maybe trying with some different fruits and veggies would be a good idea, NO avocado, chocolate, coffee, or anything like that.
Did they give you seed or pellets?
Try buying a good brand of pellets, like Harrison, I feed it to my eccy, although she's not a huge pellet fan. She prefers the meals I cook up for her-
Brown rice with chicken, pasta and mixed veggies.
Mashed sweet potato with pasta and mixed veggies.
Along with some fresh fruits during the day, a couple almonds, dried fruits, yoghurt drops, ect. She also gets one tea spoon of seed every other day. Sometimes she gets a chestnut aswell, but I have to bite it in half first coz it's too big for her to hold and break herself lol.