I recall when Sprint announced devices they would no longer support reactivating: OMA Slot Devices
If any devices on that list stayed active, it can still be used. My phone isn't on the list, which is surprising considering several of its sister phones are.
My apologies if link broke. 
Thanks!
That doesn't sound good!
They're Kyocera DuraXTs (E4277). I can't find the MEID in any menu but I found 2 numbers on the sticker behind the battery in the back compartment. One says HEX and has a 13-digit number preceded by a single letter. The other number says DEC and has an 18-digit number. The HEX number is the MEID/ESN, yes? My Tello account in 'My Phone' says ESN followed by a single letter, 6 digits, and 7 asterisks. The single letter and the 6 digits are the same as the HEX number.
Will do.
Oops, "Kyocera DuraXT" is there. Operation phone-swapping is over!
dst11, I think you're wise to abandon the thought of swapping around. Frankly, I don't think Tello is going to accept a phone swap as an 'order' for this purpose anyway.
I guess it's a rock-and-hard-place problem, though, with no other great route to keep an extremely limited use PayGo account live. Might still be worth trying if you can't feasibly keep the line another way.
Yes, I think I will let it be and whatever time period it lasts, it lasts!
Received one of those emails...either let your accounts automatically closed down or add minimum $5 data or $5 100 talk and free text, no data plans:
"Thank you for choosing Tello.
Pay As You Go credit is available for a period of 3 months since your last order was placed. If no order was placed in a period of 3 months, the credit will expire and the Tello service will be disconnected.
Please place a new order so that you do not loose your balance and phone number.
Drop us a line if you need further assistance with this.
For any other inquiries, check out our Help Center at:
Tello Mobile | Frequently Asked Questions | Help Center.
Sincerely,
Your Tello Support Team"
Nice timing... and Merry Christmas 
Did you tell support the email should say "lose" instead of "loose?"
I notice there is no deadline. Can it be more of a 'try to move paygoers to a monthly plan' thing?
BTW, I haven't received anything yet. Any moment now...
I am wondering the same. Hopefully there is a brave soul out there willing to test this. I am also curious if a device swap order results in extension. Maybe so, since possible to also port in number during device swap and I doubt Tello would expire a line soon after porting in.
Have not received any of those and the account looks normal. I will post if things change.
I'll test it for sure. I have a small PAYGO balance on both of my lines. I won't sign up for a monthly plan. I'll ride it out and see how long it lasts!
I was curious too and was ready to swap out and in but thankfully Isamorph, KentE, and rawlek helped me realize my grandfathered Tello phones won't activate again so Operation Phone-swap never got off the ground!
I haven't received the email on either of 2 PayGo accounts-- one I was planning on letting expire (low balance): and one with a higher balance that I'd like to salvage some way, but so far, Tello has declined to issue a refund for.
I'll try a phone swap on one or the other, but (personally) I don't expect it to help.
I remember someone saying he made a complaint to the FCC because Tello wasn't giving him a refund and he got his refund.
[quote="dst11"]
I remember a post on the Hofo forum mentioning the FCC refund issue.
Interesting that Tello, in addition to mentioning Tello would give Paygo users plenty of notice before expiring accounts, also said, if I'm not mistaken, it would look at accounts individually on a case by case basis, which is unusual and instills uncertainty. Yet, I'm guessing Tello's TOS probably has an "at Tello's discretion" phrase in it which would allow appraising individual user accounts as it sees fit.
https://www.howardforums.com/showthread.php/1915676-Tello-Credit-Expiration/page12
Georgiana_Tello said:
"Hey, thanks for the question!
Unfortunately, we don't have a specific period for each case, but instead, work on offering the needed time for active customers to get the notification.
No text messages for now. The idea is to check your email & account; any changes will reach your inbox, no doubt about it, and you'll have time to act on them, promise!"
"- Do I get a refund? Yes. Although every account is unique, anything that was paid for will be refunded, no questions asked.
https://www.nthcircle.com/forum/tello/2859-tello-minimum-payg-20?start=60