Ebay Seller Said to Call Microsoft to Activate Win 8.1.. Is this True?

I contacted an ebay seller who is selling a win 8.1 product key. He emailed me saying that I need to activate the win 8.1 product key by calling microsoft and entering the key over the phone. Is this correct? This is his entire email:

New message:
Yes, You can use the Product Key as long it is Windows 8.1 Pro x64bit, base on my experience after installation THE MICROSOFT ACTIVATION CENTER will send you ACTIVATION ID thru activating online only, this are several block of numbers that you have to call the FREE CALL number provided by them,
listen to the instruction, because you will be ask to estate the several block of numbers. After that you will be ask how many computer did you installed with this software, just SAY ONE. OKAY

Then you have to encode numbers of block A, block C, block D,... etc. In your computer while you are listening in the Phone, after that write the the CONFIRMATION ID on the paper BECAUSE the next time you use the PRODUCT KEY same /exact computer same OS you have already a record for your self, you can go ahead NO need for calling.

Brink said:

That's telling me the product key has been used to activate the Windows 8.1 on a PC already.

Who knows if it's actually been removed from their PC or not.

I'd stay clear of it to be safe.

Yeah my gut feeling tells me the same thing.

I have a family 3 pack Windows 7 retail Product Key that is now blocked from online activation because I have used it so much over the years. Because I now have Windows 10 with digital entitlements on all my computers and after July 29th will have no use for the Windows 7 Product Key, I could sell it on Ebay and say the same thing - you have to activate it over the phone. However, that would be illegal for me to do because that product key is the basis for two of my currently installed Windows 10 upgrades.

I'm guessing the product key in question on Ebay is probably in the same situation.