I'm sorry to hear you're still having problems! Given that it's Jan. 15th and the project is due Jan. 23rd, you might not have time to grow another batch of crystals. It can take ~10 days to grow rock candy, even when all the conditions are "just right". That being said, your project is not
a failure if you do not have crystals growing on the strings. You still did multiple trials of your experiment, and you made observations/collected data on each one. The result was not what you expected, but that is OK. Scientists (myself included) often get results that don't match our expectations. The next step is to try to figure out why
the experiment gave different results than expected. That usually involves looking more closely at the fundamental principles underlying the processes at work in the experiment. So, if you can explain the science behind growing rock candy crystals (e.g., why a supersaturated solution is required, why crystals grow, etc.), you should be in good shape. It sounds like you followed all the steps of the scientific method.
If you want to try growing another round of crystals, take a look at the advice/suggestions that Donna Hardy, a fellow Expert, gave to other students/parents. Instead of repeating her suggestions/questions, I'll point you to the topic (link below). Have you tried the things Donna suggests? In particular, did you seed the string?viewtopic.php?f=24&t=4511&hilit=rock+candy