MS Teams Data Loss after Upgrade

I recently upgraded to Microsoft365 Family upon MS Team Classic recommending an Upgrade. On 15Mar2023, during a support chat, Support Agent remote assessed (via Quick Assist) into my notebook to uninstalling my existing MS Team, i quickly warned him that he should not do that as i have not backup my data in my MS Team, he repeatedly assured me that the data will keep intact and  no data will be lost, he proceeded to uninstall and reinstall MS Team.  To my disappointment, my MS Data was lost after reinstalling MS Team,  the agent quickly transferred my case to an specialist, unfortunately issue is still unresolved till 3am in the morning.   I have reached out to Microsoft Support team again the next day (case 1051119523), to ask for help to recover my data, the agent escalated the case to Shift Lead who push me to contact MS Business Support for resolution instead, I have tried but failed the many attempts trying to reach Business Support (through the various link/channel) as I am not a Business customer and do not have a valid business email, i cant even log a case.   

I reverted back to the Shift Lead for further help but he replied that "I am sorry. My hands are tied, the issue is out of our scope of support.".  Despite few attempts asking for his help to bridge my case to Business team (whom he think can help resolve my issue) on the basis that I am not a Business customer and hence not able to reach business support, but he insisted it is out of support scope.

I felt so disappointed and helpless, my data is not recovered, there is no resolution, Personal/Home Support team abandoned me and I have no key to access to Business Support team.  I felt like I am landed in a no man's land.  I do not know how else to get help to recover my lost data 

@Tony Redmond @Russell Read @Mark Weusten