Wireless Joint

Hello everyone, first time poster and rookie hotspot user. I'm not sure if my post falls under the Nighthawk M1 category as the MR1100 is a sister of sorts, but anyway... I've been on the $55 unlimited StraightTalk wireless plan for about a year now on an AT&T locked device. It has worked decent and been quite reliable. I'm running it basically stock out of box, with changes made only to my APN. Today upon my internet going out I was informed of ST updating their TOS to include specifically VoLTE devices, making my device obsolete. Curious as to if it would be possible to edit my IMEI to resemble a VoLTE whitelisted device. Otherwise what are my best options for a plan now that AT&T has revoked their $35 tablet plan? I'm sure I could come up with an educated guess myself but I know this MR1100 can be finnicky and information regarding it specifically is scarce. All input and suggestions are welcome. Thanks!

TL;DR
StraightTalk now only supporting VoLTE devices. Looking for a workaround or suggestions for a new plan