The company probably does still have time to seek the return of any advanced or pre-paid commissions which were not in fact earned, such as due to cancellations or deaths. That's because this would be an action based on a contract or agreement (the terms under which you worked and earned commissions), and the statute of limitations, or time period to take legal action, in GA would be at least 4 years in that case, even if it was an oral (not written) agreement.A letter sent and addressed to your father would not have legal effect in the sense that they can't show that they provided you notice or served you; but they could send it to your father if they are simply trying to get hold of you and make you aware of the situation--the law does not prevent them from sending it to him. If they want to actually sue you, they will need to serve the legal papers on you, not him. However, note that if under the terms under which your father (your trainer) worked, he was liable for any commission shortfalls of yours, then he would in fact be the proper person to notice and serve.