Forza Horizon 4 wont work an nobody was able to help

My forza horizon 4 wont start.

I have an ASUS Rog strix wint i7 9750H, 16gb ram and gtx
1660ti, and it worked fine until one day.

After the two intro movies, I see a black screen and
nothing, I even video it so I can prove.

After opened tickets and chats with forza, xbox and
micrososft support, I tried all of this:

https://support.forzamotorsport.net...My-Game-is-Not-Launching-or-is-Crashing-on-PC

https://support.xbox.com/en-US/help/hardware-network/connect-network/troubleshoot-party-chat

I talked to my ISP and I sure that I have these ports opened:

Port 88 (UDP)
Port 3074 (UDP and TCP)
Port 53 (UDP and TCP)
Port 80 (TCP)
Port 500 (UDP)
Port 3544 (UDP)
Port 4500 (UDP)

I tried with several different network connection, not only
one, so the game still wont start.

I have all systems up to date: windows, nvidia, store, game,
everything

I tried with antivirus and firewall off.

I reinstalled the game for 3 times now.

I tried to restart the xbox services, tried to reset the game
from app manager.

I give acces to my PC to Xbox Support via Quick Assist, they
were unable to make the game start.

I had a ticket at forza: # 174558
the game still wont work.

SRX1517279007ID -
Refund Request denied at Microsoft, they told me that I passed the 14 day
refund policy without even read my problem, as if It was an usual request. Why
nobody understand that I paid for an app and it is not working?

I ve requested to talk
to a supervisor on https://partner.support.services.microsoft.com.

I talked for days with guys at xbox support because they say
that Teredo wont work and this is the reason my game won’t even start. Is this
true? Teredo cause the game a black screen? I tried several different network
connections!

What shoud I do more? I am very upset because I am taking for
days, weeks, with all kinds of support, they put me the same questios over and over
again. For me is very simple: I paid an app that wont work anymore. Sollution?

1. Make the game work.

2. Full refund.

I am willing to let you, or anyone else chek my PC with VNC
or Quick assist, and try to make it work, but if it will not work, I want a
full refund. My job is tech support and I know what it means, I know that I have
to repeat the problem, but now I think is too much. And at my job, I resolve
the clients problems, with technical solutions, and if this is not possible I resolve
the problem with a commercial solution like a refund. It is common sens that if you have a product that don’t work you can
get the money back. I DO NOT HAVE AN ORDINARY PROBLEM, SO I DO NOT EXPECT AN
ORDNARY SOLUTION.

I am
still in good faith to let you guys use a vnc solutions to make the game works.

I am the only one with this kind of problem with this game? Because in all my life I have not encounterd such problems with the games I bought.

Thanks!

:)