Have you tried speaking with the broker to see how they manage their demo accounts, I believe there are some terms guiding. And I don't see any reason why a broker should restrict a trader from demo practice. What some do is set a specific period for demo, then you can reopen again after that period. I think maybe you should speak with your broker if you haven't already done that!
Practice in demo account, especially for beginner, they can backtesting with free from risk, many system trading, if likely demo account already expired they can open again new account and test new system trading, if they felt confident in demo it will help later if already start in real account