My supervisor issued me a reference letter for my current job and I have submitted all my documents and recieved AOR on 11th October 2018. But I got to know after my profile submission that my supervisor has resigned and November 22, 2018 will be his last working day. His official contact details are mentioned in the letter. If Visa Officer tries to connect with him, he would not be contactable. I don't know now what to do in this case. Can anyone give suggestion?