Questions-Answers:
1) "Will I be able to buy a code from you and activate it after the end of the subscription?"
Yes. These codes are suitable for renewing subscriptions on all accounts. The main thing is that you do not have an active subscription. That is, before activating this subscription code, Live Gold, Game Pass or Game Pass Ultimate must expire.
2) "I have an error that this code is suitable only for NEW USERS! What should I do?"
This error is ONLY because you have an active Live Gold, Game Pass or Game Pass Ultimate subscription. You need to wait for the end of the subscription and then activate the code.
3) "How long are these keys?"
The code must be activated before 08/10/21, but must be activated immediately to avoid various problems.
4) "I have an error. I could not find the code. Please enter it again. What should I do?"
Try to activate the code in a different way. Microsoft is sometimes very dumb.
5) "I have an error. Read the instructions that came with the code. What should I do?"
You most likely have a region in the settings that does not support the Ultimate Subscription - Ukraine, Belarus, Latvia. In the settings, change the region to the USA or Russia, for example, and everything will work.
6) "I have an error Failed to process your payment. What should I do?"
Try to activate the code in a different way. Microsoft is sometimes very dumb.
7) "I activated the code but there is no subscription. And now it says that the code is activated."
There is a glitch that the subscription does not appear immediately. You need to re-enter your account, if it does not help, then wait a while and also re-enter your account.