Hello,
On Wednesday 29.9.2021 I bought serial code in web side (www.key4you.cz) for Dialbo 2 Resurrected, not throught Battle.net then succesfully redeem it in my Battle.net client, but still I don’t have an option for install the game. In Battle.net client there is still showing me BUY button, instead of install button for the game. It seems, that after code activation, game was not assing to my game library in Battle.net.
Could you please support what should I do now?
Thank you in advance.
To claim a valid code you would go to your Account on the website and claim the code there. It will tell you if it is valid or not. Once done, restart the launcher (or sometimes PC) which forces the launcher to pick up the account flagging and allows access to a download.
However, you bought the key from a third party site which is not a good idea at all. Those are often shady, steal your financial payment info, steal your money. The scam is that they buy a valid “gift” key then give you time to claim it. You THINK it works, but then the quickly refund it so they get the money back and you are out your money as well.
Seeing as you bought it from them, if it does not work you have to follow up with them for a refund or new key.
NEVER buy from an game site besides the game vendor. This goes for pretty much any game.
You might also want to edit out the website so others don’t get scammed.
I really hope this is not a scam, and hope restarting Bnet helps.
I made possibilities you propose, but without success. The code seems to be valid, codes from this webside were aslo valid (for Starcraft I + II) in the past.
When I try to put the code in Account on the webside, it show me the same as in the Battle.net client:
You’ve already claimed this code.
You can only redeem a code once. If you didn’t already claim this code, please make sure you entered it correctly and try again. For more information, please visit our Support Site.
Maybe one idea - could not be the OS problem? I have the latest Windows 7 and I re-installed the client with also deleting the rest of files as support possibilities advices.
Ok, you did claim it successfully then. That is good and it seems to still be on your Bnet account. You can always double check under your Games list on the website.
Win 7 is below requirements, but you should still be able to install it even if it won’t work.
Totally exit the launcher and close it. Check task manager to make sure NO battlenet applications are running. Sometimes this requires a PC reboot.
Restart the launcher and log in. That should have updated it. From there, go to the D2R tab and the Buy button should say Install. Double check that the drop down list over the Play button is on the Live game release and not a Beta or something else.
Make sure you are logged in to the Bnet account on the launcher that you claimed the key on.
If that does not work you might need more help than a fellow player like me can provide.
Here is the process I made:
Uninstalled Bnet + deleting rest of folders C:\ProgramData\Battle.net and then restarted PC.
After that installed Bnet client again, logged in, checked D2R - only BUY button. Checked also on web side and there’s the same, only BUY button.
Downloaded D2R-Setup from web side account and tried to install it with logging in, sent this message:
https://us.battle.net/support/en/article/32512
I am running out of ideas what else shall I do.
info:
Day later (30.9.) after purchasing the code and error appearing, I created also a ticket in a section Account, App, & Shop, unfortunately with no response yet, that’s why made a new topic here, due to hunger of playing D2 
Good. There are a lot of tickets in but as long as you got a ticket number it has been submitted.
IF you go to Account Management and it still does not list the game under your Summary after claiming the key, I really think you got scammed and they refunded. Blizz staff can confirm that though once they look at your account. They can see if a key was added then later refunded or removed.
Here is Account management if you want to check. That helps prove if the key is actually on the account. Every game you own will be listed on the Games and Subscriptions page.
And that is strange, because D2R is not here. Only Older purchased games.
Do you think I should send immediate feedback to web store or wait until Blizz staff check, what happened with this key as you wrote?
It depends on if they have a refund policy or not. What is the website’s refund policy? Will they just refund you or do they require proof from Blizz the key is removed?
If the website does have a refund policy, you might need to present them with evidence from Blizz the key was claimed and then removed. I honestly avoid all third party key selling sites for this reason. It is so often a scam.
Terms and conditions indicate, because the goods have digital content, are not delivered on a tangible medium and are delivered with the prior express consent of the buyer-consumer before the expiry of the period for withdrawal the purchase contract that he has no right to withdraw from the contract .
Before now, there wasn’t problem with any sent code and this webstore is well known, several times awarded as shop of the year and recommend by 95% od customers.
But due to this I will need to wait until official ticket solving, maybe have to send a proof from Blizz to them with explanation what happened.
Meantime I will have to update OS to Win10 for sure anyway.
For now thank you for your support MissCheetah 
Edit 2.10.2021_
Well, it seems to I have a little luck today.
I received an answer from Blizz staff about my ticket and now it is clear.
Code content is €40 - exactly for D2R price, so I only marked D2R in menu as a favorite game and in the balance menu paid for it’s buying.
Now it seems simple now and I am already downloading. However, I will send a message to web store, to avoid misunderstanding next time, they should explain directly what you exactly got with certain codes.
Anyway, thank you a lot for your support once again, I apreciate it and hope, that next time It won’t be necessary to bother you;-)