Error using voice tgexting with Siri

Whenever I try to send a text message with using Siri the sender's name is someone else from my contacts not me. First it shows up with this " _$!<mobile>!$" as a contact name. Then another message from a different person in my contact list as the sender. It says that says the message was "not found or invalid. For help, reply with `HELP`". So I replied "help" it comes back saying "Syniverse Marketing Alerts: Get 10 msgs/mo...."

Have my contacts been hacked? Any idea how to resolve this?

Thanks.