Is it true that a digital cable has to acclimate to your system?

It could well change tonally a little for sure, was it bought new or used?
If used it is unlikely to change to any audible degree
If you do not like the sound I cannot see it changing majorly for the better to your ears.
Every cable is going to be different in other systems and to other ears.
Give it a couple days sure but if you are not happy see if you can return although from the complete gobbleygook the seller already gave you they might not.
Unfortunately if nothing actually wrong and you just do not like the sound it would be very hard to force them to accept the return.
Play it nice and maybe they will.

Good luck!

Thanks much!

Hello Audiogon Friends - 

I am delighted to say that the Kimber Orchid AES/EBU cable I bought is sounding better and better.  So there must be such a thing as "break-in" for a digital cable,  even if it is a used cable.
At first,  I noticed a very grainy treble coming from my 802D's.  But now,  the soundstage is wider and deeper,  and I am really beginning to enjoy it now.
Thanks for all of your input.
Sincerely,
Ted.

No.

It’s the same with headphone burn-in myth, all that happens is your ears getting used to the sound.

A digital cable is just bits, the only error being timing, which is jitter, which is a raised noise floor, nothing to do with tonality and soundstage.

Thanks,  but I have to disagree.  There is definitely a clear improvement.  I was a piano tuner for 15 years and my ears are very senstive to what they are hearing.  I think Steve from Empirical Audio is right.  He said,  "The explanation is nonsense, however shipping any electronic equipment causes static charge to build-up in the dielectrics. It takes about 3 days for this to dissipate. Also, the new connections probably have to adjust at the metal-metal boundaries. It should sound better after 3 days of break-in.
Best,
Ted.