Network Connection Issue

[GrizBiskit]

I've been using an S4 for about 2 weeks now, no problem. Last night I realized a text I sent never went through, and today my lock screen says "No Service" or "Searching" (despite the device showing full signal). I can't send/receive calls or texts, and I don't use a data connection. This SIM is also new (~2 weeks), and the device is neither rooted nor running a custom ROM. I've tried everything I could think of, like:

• reboot
• pull battery and SIM
• confirmed APN settings on t-mobile site
• tried alternate, non-"LTE" APN (epc tmobile com)
• tried every network mode setting (GSM, GSM/WCDMA, etc.)
• reset APN to default
• turned on mobile data connection
• manually scanned for networks (wouldn't connect to AT&T or T-mo)
• select network automatically (wouldn't connect)
• complete factory reset

I tried my SIM in another T-mo phone and it works; tried a different SIM in my S4 and it doesn't work. All other T-mo phones in my household are working fine. My S4 is definitely the problem here, but I don't see how the radio would just stop working after 2 weeks.

Has anyone else experienced/seen this? I never have, and it's driving me up a wall. I'm going to try my local T-mo store tomorrow, but I was hoping to fix it before then. Any help is greatly appreciated.

EDIT: I purchased the phone new on ebay. For a minute I thought the seller might have reported the phone stolen, but I checked the IMEI and it's clean.

 

[cryptic3]

Ive experience this but my service came back in about 25 minutes I did reset reboot battery pull sim pull it just came back on its own

Unrooted Samsung Galaxy S4 Up and Running
Rooted Mytouch 4G Slide retired
Rooted T-Mobile Sidekick Touch Obliterated
Rooted Mytouch 3G Slide Lost
Rooted T-Mobile G1 Dead

 

[GrizBiskit]

So I finally got to T-mobile today. Unfortunately, my hunch was right: the IMEI is blacklisted. Their in-house system must be more up to date than their web IMEI checker.

Time to solve this issue elsewhere.