Blocked SIM card

That means that other phone was blacklisted which caused your sim to be blocked. You need to call ATT to get the imei associated with your SIM card updated back to your original phone.

Thank you for answering. I call customer service a few days ago with no help. They said I had to pay $36  but couldnt give me a clear answer as to why and also said I couldn't even use my plan that I'd paid 2 days after I was blocked from network use. And even said I could be kicked out of my multi-line account. I asked to speak to a supervisor and the representative told me no ma'am. I asked to speak to anyone other than th representative I was speaking to bc she became very rude and asking personal questions that was not related to my service. She finally said they would call me back but didn't ask for a number to call me back on since mine was obviously blocked and didn't call back the from I did make the call from. I don't understand why I would be charged and why I can't use my service that I've paid for. My service was renewed October 14th and my network was blocked October 12th. This has been very frustrating as it's difficult for me to use someone else's device since I'm unable to use my own. What do I need to tell Att customer service when I call and should they be charging me $36 to unlock my account and if should why? 

Sorry for the typos. Trying to do this quickly since I'm borrowing a phone. 

Hi Sheshe0444, we understand the importance of being able to use your device, we want to take a closer look at your blocked device!

Please check your Direct Message Inbox (it’s the chat icon next to the bell icon in the upper right corner of the Forums) and reply back. In the meantime, learn how to restore wireless service on your device.

We look forward to hearing from you, Again, keep an eye out for our DM!

Rhoda, AT&T Community Specialist

Whoever told you that there was a $36 charge for reactivating your existing service was full of potatoes. That is the charge for changing the phone number which is not what you want to do. You simply want to call and make sure that your phone number and SIM card is associated with a valid phone.

It might be easier to do this at an AT&T store. Bring your sim card, a valid AT&T phone, walk in and explain what happened.

In the future never put your sim card in a phone without doing an IMEI check.

https://www.att.com/buy/byod/identify?devicetype=phone

Thank you!! I am relieved! I knew that representative was wrong and out of line and claimed to be the manager. I always been treated like a valued customer until the conversation with her.