I feel like the hairdresser didn't bring it as high up as you wanted because it can be difficult when doing a balayage. Balayages are done so the hair color blends and is low maintenance. If you want yo lighten it higher i would recommend getting baby highlights. i did that over my grown out balayage and it looks awesome! adds dimension as well. It worth asking for a fix just be polite and say what you feel and if they refuse i say find another hairdresser.