Message Thread Separation?

[Dahrkness]

I have a Droid RAZR and recently upgraded to ICS. it was working fine until two days ago. I was texting a friend using there Pinger account. And it started separating our conversations. One message he would be on a regular number format, next my phone would make a new message thread and the number would end in @textfree.us. Now last night, I was texting him and it now has two different threads of the @text free.us. it will only let me text in one and his replies show up in the other. If I text in the one with his responses, it transfers my messages to the other thread. What is going on? Could really use some help. Am technically challenged. Thanks