Lost my entire messaging roll-over balance (again)..

Not 100% sure, but from what I can remember, my messaging roll-over balance was around 5,000 messages last time I looked (maybe a month ago, and only text occasionally).  I've been on the AT&T Prepaid 10¢ Per Minute plan for many years (was originally on the 25¢/min plan, then later the 10¢/min 'smartphone' plan) with the 200-message add-on package set for auto-renew (also had this for many years).

Anyway, I randomly logged into my account today (was considering buying additional lines for my old phones) and noticed that the messaging add-on was removed completely (this happened twice before over the past decade, due to hitting a max roll-over cap).  Called up AT&T Prepaid support thinking they would understand the issue, since it was noted on my account that it's happened before.  Instead, the representative wasted about 45 minutes 'researching' the issue, putting me on hold, and the entire time kept giving me random made-up excuses as to why this happened (insisted that add-ons don't roll-over on my plan, or that it was probably my Xperia phone that I've been using for over 5 years, or that I let the add-on expire, even though it was set to auto-renew with a sufficient balance.  I also provided him with the previous solution of simply crediting my account $20 then using that to purchase 2,000 messages to cover at least part of the loss.  He adamantly said he wouldn't do that at all since they had already credited me $10 years ago to fix a roll-over loss when this happened before.  EDIT: Thinking back, I recall the last rep years ago telling me that if it ever happened again, not to worry, and to just call back in and they would make the proper account adjustments again.)

Eventually got upset enough and demanded to speak to a supervisor, who eventually understood the issue and offered to credit me $10 and used it to apply 1,000 messages (though she explicitly stated that I would have to use most of that, because the max messaging add-on cap for my plan is 1,000.. which I'm pretty sure it used to be, and was then upped to 5,000 and again to 9,000).  I'm 100% certain that my add-on was set for auto-renewal, but don't remember exactly my messaging balance (pretty sure it was around 5,000) so I guess my add-on balance could've been over 8,000 and hit the current cap (see current caps as officially stated in the link below).

Wasted over an hour dealing with this today (mostly speaking to a rep that should honestly be fired) and ultimately lost several thousand roll-over messages.  I've been an AT&T Gophone/Prepaid (and DirecTV) customer continuously for over 10 years, rarely even using the service I've paid for, and shouldn't be given this much grief while trying to resolve a reoccurring issue that has happened through no fault of my own.

As an aside, an elderly friend of mine that is on the same plan has to deal with a similar issue once a year (doesn't use his phone and keeps hitting the $500 max account balance).  Though oddly enough, support has always been able to help him out (gave him a free phone once and gave him a free year once or twice).  I honestly don't care and shouldn't need to know what the max add-on balances are, but instead of the add-on dropping off the account entirely, it should continue to auto-renew and extend the expiration, but could stay limited to the max limit that it's capped at (max account balance should do the same, and adding $100 for a year's service on a $500 balance should just add the 1-year expiration extension).

If any AT&T customer care personnel can look into this a little further, please let me know, I would really appreciate it.

https://www.att.com/esupport/article.html#!/wireless/KM1045152

UPDATE: Printed out a PDF file back in February of this year, showing my current balance and rollover amounts (probably worrying about whether I'd hit a cap again), and based on an additional 200 add-on messages for 7 cycles (not including any amount used), at most I would've had 5,822 roll-over messages left.  This is nowhere near the 9,000 max roll-over messages (as officially stated in the link above), and even if the cap was only 5,000 there's simply no way that I would've used 822 messages during that time (50 to 100 tops, and that's factoring in longer multi-part messages).  So then what exactly caused this issue?  Was 2nd-tier support correct about the 1,000 message cap, and if so, when was this changed (since I obviously had well over that amount)?  She also mentioned that the system could remove the add-on package if it wasn't being utilized, even though I sent 6 messages earlier this week.  And finally, I found an AT&T free notification message sent 6/24 that I never noticed (get a lot of these at inopportune times of the day) and it stated "your 200 messaging plan was removed on 06/24/18 from automatic monthly renewal".  This should've been the day that my add-on renewed, and I made absolutely zero changes to my account (last login was probably back in February).  So why did this happen?  How do I keep it from happening again?  I pay AT&T, keep a sufficient and active balance with everything set to auto-renew, so now why in the world is this something I should have to constantly worry about??