Nate already brought up the abuse aspect. Age and relationship aside, consent in sexual matters (and regulating the ability to get sexual relief is one, even if it is not a sexual act) can always be revoked under any form of right to sexual self-determination. The fact that your ability to consent was compromised in the first place by your age and status as a dependent just adds to that.
I want to add that as a dependent, your parents have a duty to provide for your well-being, and they cannot legally cut you off if you refuse chastity. That said, insisting on your rights might be a bit of a struggle unless you find good support for it - still worth knowing your rights in a negotiation with your parents though, so read up on family law.
As for your situation, you have not told us much about yourself yet. These questions may be a bit inappropriately invasive, particularly considering your age, so do not feel guilty for not answering questions that make you uncomfortable:
- Was there a specific reason for the locking, or just an immediate response to your ... development?
- Do you get relief breaks, or at least have wet dreams? It is unhealthy to not ejaculate for several months, let alone years.
- Does anyone other than your parents know about your locked state? You might be able to confide your unhappiness about your arrangement in them.
- What device and lock are you subject to - you might be able to "sneak out", so to say, but it requires a lot of privacy to not get caught immediately.
