I did the same thing 10 days ago.

I have the same situation as yours.

I sent the prority mail with confirmation service for request of relink and it took 7 days to arrive the TSC center.It supposed to deliver on the second day.

I also sent the request by fax on the second day after I sent the prority mail.Two days later,my approved EB1a I140 and pending I485 got Updated on the website.I don't know if the relink is successful.Do not get any other information.Still waiting.

I just did all the things as Derlin told in this forum.So you can get the same information by seraching "Derlin".

Good luck.