Is it legal for my apartment complex to not provide a utility bill?
Legal? Maybe. What they should be doing, and you should be asking for, is a detailed breakdown in print form, or email as to your fees broken-down and itemized. If they say its not possible then ask them to either provide that response in writing or email. Then Id be calling some city agencies and see what theyre actually required to provide to you. Otherwise you might find yourself paying a portion of others usage for everything.