What does the Drs office staff tell you when you call?
Maybe he didn't take notes?? or they aren't transcribed ? something got lost??

there has to be some reason or excuse

Are they close enough you can go in person and speak to the office manager or ? higher up until you get an answer?

If you need to make another appt to have his memory refreshed it might be worth it. that is a long time to be waiting for a report & due to the time limits on the LTD.

I'd really be firm about getting an answer -- it is needed now esp due to the LTD cut off time.
I'd be very nice at first but if they stonewall you and can't or won't give you any help or suggest any options - then get tough- ask who you can report this to etc.

Is his office a group of Drs or only him?