Recovering disconnected cell numbers

Called Cox Mobile to get our port-out PINs two days ago. The tech texted them to me. I explained I was going to another carrier and would be taking our numbers. Before the call actually ended, he disconnected our service. The calls my wife and I were on were cut off and since then I've been trying to get our old (20+ year old) cell numbers back.

Initially (within 60 minutes of the disconnect), I was told the numbers were lost forever. Period, the end. I kept pressing and ended up talking to someone who seemed convinced his team could resurrect the numbers. They actually have a team dedicated to this. He was tremendously helpful and told me they'd get the numbers back "100%." Well, the timeframe he gave me came and went without success and instead we received new SIM cards that apparently have new numbers attached to them. Online activation for Cox advises our old numbers are not eligible for transfer. The very helpful guy gave me his contact number but it requires an extension (which he didn't give me) so today I've spoken to another 5 or 6 reps trying to get help. The last guy I spoke to (in the loyalty dept) told me he'd be talking to tech support and getting back to me. He never got back to me.

Anyone know a way to get the old numbers back? May seem a small issue, but the numbers are tied to business, to online verification of accounts, etc., for over 20 years. Any help would be appreciated. I cannot believe that an inadvertent keystroke on Cox's end could flush away our old numbers in an instant without any chance of retrieval. Seems other carriers (even MVNOs) can retrieve the numbers in these situations.