This is an forum that is mostly visited by users and not an "support" website. If you want to contact support, you have to mail/call them directly.
Now - with this out of the way, I will try to answer your question (keep in mind this is an "as far as I know" answer).
The LE version that's included in the Key's magazine is completely legal. As long as the serial/key is not registered it is also legal for someone else to use it. The key magazine is (even now) still available to buy, so it is an cheap way to get Wavelab LE.
I guess it's not against any law to re-sell the magazine complete with serial/key. However - I should suggest to check if you cannot buy the complete magzine (including transport costs) cheaper directly from the publisher. That way you are absolutely sure that everything is completeley legal.
Keep in mind the key must be unregistred. If someone else already used the key/serial you are out of luck.
Personally I ordered the magazine from the publisher, and after registering the LE version I upgraded that version to the Wavelab Elements version at the Steinberg online shop. This is (an bit) cheaper than buy the full Elements version...
. I also put the registration on my USB licener (that I also use for Cubase 8 Pro and an few instruments like Padshop pro etc.), so I can use the program wherever I am.