3G sunset, prepaid appeasement refund

I've been using AT&T Prepaid for years, completely happy.  Now, with the 3G sunset, our AT&T microcell no longer works and we have NO coverage in our area.  I've been on the phone (landline) with AT&T for the last five days; spoke to over a dozen agents, who all tried to find a solution, but ultimately could not.  I had to go with another carrier, which hurts because I'm a former AT&T employee, now pensioner.  One agent assured me that there is an "appeasement" (her word) refund program in place to return now-unusable Prepaid balances.  It's close to $100.  She gave me a particular number to call -- but they could not even access my account.  Just today I've spoken to five different agents, without result.  I have my actual account number (diff from the phone no.) -- but that doesn't seem to help either.  How can I get this sorted out?  I didn't WANT to leave, but with no coverage there was no choice.  So AT&T has my money, and I deserve a refund.  PLEASE HELP.