Legal Question in Entertainment Law in California

You don't say whether you son is a minor, but I assume that he was at the time the contract was entered into. You also don't say the nature of the addendum or whether it materially changed the contract. There isn't enough information in your post to answer your question about whether the contract is good, and you probably don't want to give more information in a public forum. My suggestion to you is that you consult with an attorney who can review the documents and advise you specifically on what your obligations and remedies might be. In the meantime, if you have spoken to someone with the state who says you need to file a petition, you should consider following up on that. Again, you would be better off having an attorney look at it before you file.

Keep in mind that trying to save a few dollars on an attorney now could end up being much more expensive to you later. Most attorneys will tell you honestly whether they can help you before you have to pay anything.