After Buy Minecraft for Windows10, I star a Realms Plus for playing with my friend with a Nintendo Switch. After the free-month trial I pay for the first time from the game on my PC (the same W10 PC that open that realm) and after click the "renew" button the game redirected me to the Windows Store for actually purchase the subscription. And everything goes fine.
Now, at the end of the first purchase month, I need to renew for the next, and now when I click on the Edit menu of my realm the game says " You started your subscription in the Windows Store. You can only extend your subscription there." and when I press the "manage subscription" on the same page that the last month says that I can extend my realm, try somehow to load something where was the extend button the last month.
Nowhere in the Microsoft Store, I can find where I should buy or extend or manage the subscription on Realms Plus. I'm not the only one who has this problem, because I found this ticket on the Windows Support Page https://answers.microsoft.com/en-us/windows/forum/all/cant-renew-minecraft-realms-subscription/d27ef00d-0b26-4065-ac39-6ba276359d7d on this day (28/06/2020) other 22 people have the same issue.
What we can do?
Edit: Is even impossible to OPEN a new realm in the game.
Edit2: In the 1.16.1 the EXTED button is back, and working for me. But after the extend the text still say "0 days remaining" even if I pay the renew.
Edit3: 14 days after paying my realm, the same realm expired, in that time, on the setting page says 0-day remaining. When expired I contact Mojang support, useless as usual, they didn't respond with an actual response, with a reason why all of this is happening, they just say in a nutshell "ask Microsoft for the paying stuff". I call Microsoft support for a refund for my subscription and they immediately gave me, then I paid again, for a new whole month; now, the setting page of my realm says "Renew every 30 days" in the Duration section.
Try to ask for a refund and purchase again if you don't see "Renew every 30 days" in the Duration section.