Backwards compatibility issue with downloading your data and can not download your xbox...

3 month's ago i was playing gta 4 and all of a sudden i disconnected from xbox 360 live when i am still connected to the Internet om my series x. So i restared my game shoud fix it right. Well, i restarted and all of a sudden it didnt download my information or even log in to my account. So i tried to delete my account on xbox 360. That was a BIG mistake. I couldn't download my account. Everytime i tried it says its something wrong with my connection. But i am connected to the internet already. So i looked for solutions online. I tried disconnecting my mobile hotspot (i dont have a router because i have unlimited data on my phone so i didnt need a router) for 30 seconds and even more, tried clearing my xbox 360 storage, changing my ip, my Mac adress, port even DNS, i tried reseting my xbox series x to factory new, i tried trouble shouting it, I tried re downloading my gta 4 and even other 360 games i own both disc and digital, i even cleaned the series x. Even changing my hot spot settings in my phone. NOTHING WORKS. I tried reaching out to Microsoft support i wrote down everything i did. I didnt get an answer from them. I tried contacting xbox. But, in sweden you cant phone them or chat to a it worker there. There is nothing. Thats why i sent my report to Microsoft. Now am asking. What do i do now? How am i gong to fix this problem? Do i need send my xbox to an engineer to fix this issue?

:)