MMS not working?

So sorry to hear about this experience, Sezro. We want to help! We value your privacy and security. Due to the nature of your concern, we would like to authenticate your account, but for us to do this in a secure way we need to take this to a private channel where we can discuss private account information. Please send us a private message along with your phone number, the PIN and a brief description of your request. To send a private message, click on any of the social care agents user names and select the option send this user a private message.

 I have a  iphone . It was originally on AT&T's network will I need a new sim. It is giving me an error when I try to connect to it. 

Hi, Stuckon3g. Please enter the Device ID here https://activate.boostmobile.com/bring-your-phone?intnav=TopNav:Phones:BringYourPhone or visit a Boost Mobile store to check if your phone is eligible. You'll need to purchase a new SIM card when you Bring Your Own Phone from a non-Boost Mobile wireless provider. Your new Boost Mobile SIM card will allow you to use the Boost Mobile network. To get a Boost Mobile SIM card kit, buy online, visit a Boost Mobile store or contact your local Walmart for product availability.

Understood. We received your private message. We'll continue to assist you in private.