T-mobile Career Pay Scale I Cannot Send Sms To My Messenger Contacts?

I cannot send sms to my messenger contacts? - t-mobile career pay scale

I installed Yahoo Messenger 8.1. I can not send SMS to my contacts in Messenger. My location is Germany, with my career, T-Mobile in Germany. I have tried to SMS in Germany, USA, Romania, to send, etc., is not possible. Please answer as well. Thank you!