Windows Chat support,Microsoft Store & Windows activation Issues.

The Microsoft Store app on my freshly installed Windows 11 Pro 23H2, is not opening since I could not activate my Windows 11 using my digital signature which was connected to my previous version of Windows 10 that subsequently updated to Windows 11 Pro 23 H2. Neither online chat support is accessible nor their phone callback is working though I have placed three callbacks out of which one was cancelled after 3 days! In the meantime, I am unable to activate Windows 11 though I have tried several methods including buying a new activation key! The new activation key also failed to connect to my digital account. Different types of Errors are coming. Although I have purchased a new product key, an error saying the product key was used on another device. Searching for any such device left me blank as no such devices could be traced! Hence, I am unable to activate Windows 11 for which I wanted to contact support, but that also failed! What is going on and what is the solution to my problems? I have also tried to activate with my old product key which I used for my Windows 10 PC for the first time. I have made no hardware changes while upgrading to Windows 11 Pro 23H2. Then what is the problem I cannot understand!