[the incompletely imaged upper cervical spine there is multilevel spondylolisthesis in degenerative disc disease.]

Your dr should be able to use this part of the information to prove that you need a full MRI.
Seems like his office should have followed up and requested the c spine MRI again , and saved you a visit til the c spine MRI results arrive.. But that's just my thinking..

Have you called the office and asked about it since spondylolisthesis/DDD is showing on the head MRI?
Why go for an office visit when this MRI shows more imaging is needed?

[ multilevel spondylolisthesis in degenerative disc disease.]
I can't tell much more from the info because it does not say if it is severe, moderate, mild , or if any nerves are being impinged or the cord affected..

I have no clue one the [hypoattenuation of the marrow could reflect artifact or red marrow reconversion]

Have you gotten any PT for pain relief/soft tissue etc?
Was there an injury that set the pain off?