Until now , I still have not yet got a respond from "yogg" as he said.
So that's the second reason I have not used that account to do anything.
You must ask yogg to give signed message. You may get into trouble sooner or later without it.
I kept BTCBLOGGER's funds until he provided a signed message stating he asked me to sell his account.
I got it, then I released the funds. Now I just sent to OP that signed message from BTCBLOGGER and another signed message from me, stating I sold such account to OP on behalf of BTCBLOGGER.