New SIM card but No Network Connection

Okay, so here’s my issue:

I’m switching from US Mobile to Red Pocket Mobile. The network I used with US Mobile was Verizon. I got my number ported to Red Pocket and the new SIM card activated, but there’s No Network Connection whenever I put the new SIM card in and start my phone. My phone seems to be detecting the new SIM card because it says “Service provider update. Your device will restart to configure features supported by the new SIM card” but when I go to the SIM card status, everything is Unknown and Disconnected. My phone number is also Unknown.

I’ve checked the APN and the new SIM’s network - which is AT&T - shows up with all the information matching what Red Pocket it should be; I’ve even manually added the APN information and selected that one but nothing changes. Nothing shows up under Network operators. I can click Network operators but it just allows me to choose between Select automatically, Select Manually, and Default Setup.

When I put my old SIM card in, I still have No Network Connection but can make calls - my phone will ring and I’ll get a recorded line saying I’m being directed to where I can finish my call after making a credit card payment. I can’t send texts. But my SIM card status changes to Verizon and all its information; the APN shows the Verizon APN; and Network operators shows Verizon below it and I can’t select it.

I bought this phone unlocked from Swappa and have been using it with US Mobile since April 2019 and have had no problems before now. My phone isn’t on Airplane mode. I’m not getting a SIM Network Unlock screen. US Mobile and Red Pocket have only met the baseline of helpful. I’ve chatted with Support from both carriers for hours and both sides think it’s not an issue on their side.

US Mobile says they released my phone number and that they don’t have the ability to lock phones. I asked if Verizon could somehow lock my phone through them since I was using Verizon’s network, but they told me no. Red Pocket says the problem could be either 1) my phone is locked or 2) an issue with the SIM card. They said it was more likely to be an issue with my phone than with the SIM card because they say there are no issues with the SIM card on their end. Supposedly, I’m supposed to get a call (on my home phone) or an email from a Red Pocket tech who has more experience, but I highly doubt someone will contact me.

I’m frustrated and tired and I just want this solved so that I can use my phone as a phone again. If there’s any other information that I need to provide, then I will but I really need help.